None Computing title VMware vSphere 7.0 vCenter Appliance Photon OS Security Technical Implementation Guide version 1 releaseinfo Release: 4 Vuln_Num V-256478 Rule_ID SV-256478r958368_rule Severity medium Rule_Title The Photon operating system must audit all account creations. Vuln_Discuss Once an attacker establishes access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to create an account. Auditing account creation actions provides logging that can be used for forensic purposes. Check_Content At the command line, run the following command: # auditctl -l | grep -E "(useradd|groupadd)" Expected result: -w /usr/sbin/useradd -p x -k useradd -w /usr/sbin/groupadd -p x -k groupadd If either "useradd" or "groupadd" are not listed with a permissions filter of at least "x", this is a finding. Note: This check depends on the "auditd" service to be in a running state for accurate results. The "auditd" service is enabled in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add or update the following lines: -w /usr/sbin/useradd -p x -k useradd -w /usr/sbin/groupadd -p x -k groupadd At the command line, run the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist and may reference older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256479 Rule_ID SV-256479r958388_rule Severity medium Rule_Title The Photon operating system must automatically lock an account when three unsuccessful logon attempts occur. Vuln_Discuss By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-force attacks, is reduced. Limits are imposed by locking the account. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128 Check_Content At the command line, run the following commands: # grep pam_tally2 /etc/pam.d/system-auth Expected result: auth required pam_tally2.so deny=3 onerr=fail audit even_deny_root unlock_time=900 root_unlock_time=300 # grep pam_tally2 /etc/pam.d/system-account Expected result: account required pam_tally2.so onerr=fail audit If the output does not list the "pam_tally2" options as configured in the expected results, this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-auth Remove any existing "pam_tally2.so" line and add the following line after the "pam_unix.so" statement: auth required pam_tally2.so deny=3 onerr=fail audit even_deny_root unlock_time=900 root_unlock_time=300 Navigate to and open: /etc/pam.d/system-account Remove any existing "pam_tally2.so" line and add the following line after the "pam_unix.so" statement: account required pam_tally2.so onerr=fail audit Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256480 Rule_ID SV-256480r958390_rule Severity medium Rule_Title The Photon operating system must display the Standard Mandatory DOD Notice and Consent Banner before granting Secure Shell (SSH) access. Vuln_Discuss Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance. Satisfies: SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088 Check_Content At the command line, run the following command: # sshd -T|&grep -i Banner Expected result: banner /etc/issue If the output does not match the expected result, this is a finding. Open "/etc/issue" with a text editor. If the file does not contain the Standard Mandatory DOD Notice and Consent Banner, this is a finding. Standard Mandatory DOD Notice and Consent Banner: "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "Banner" line is uncommented and set to the following: Banner /etc/issue Navigate to and open: /etc/issue Ensure the file contains the Standard Mandatory DOD Notice and Consent Banner. "You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions: -The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations. -At any time, the USG may inspect and seize data stored on this IS. -Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG authorized purpose. -This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy. -Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details." At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256481 Rule_ID SV-256481r958398_rule Severity medium Rule_Title The Photon operating system must limit the number of concurrent sessions to 10 for all accounts and/or account types. Vuln_Discuss Operating system management includes the ability to control the number of users and user sessions that utilize an operating system. Limiting the number of allowed users and sessions per user is helpful in reducing the risks related to denial-of-service attacks. Check_Content At the command line, run the following command: # grep "^[^#].*maxlogins.*" /etc/security/limits.conf Expected result: * hard maxlogins 10 If the output does not match the expected result, this is a finding. Note: The expected result may be repeated multiple times. Fix_Text At the command line, run the following command: # echo '* hard maxlogins 10' >> /etc/security/limits.conf Not_Reviewed Vuln_Num V-256482 Rule_ID SV-256482r958402_rule Severity medium Rule_Title The Photon operating system must set a session inactivity timeout of 15 minutes or less. Vuln_Discuss A session timeout is an action taken when a session goes idle for any reason. Rather than relying on the user to manually disconnect their session prior to going idle, the Photon operating system must be able to identify when a session has idled and take action to terminate the session. Satisfies: SRG-OS-000029-GPOS-00010, SRG-OS-000279-GPOS-00109, SRG-OS-000126-GPOS-00066 Check_Content At the command line, run the following command: # cat /etc/profile.d/tmout.sh Expected result: TMOUT=900 readonly TMOUT export TMOUT mesg n 2>/dev/null If the file "tmout.sh" does not exist or the output does not look like the expected result, this is a finding. Fix_Text Navigate to and open: /etc/profile.d/tmout.sh Set its content to the following: TMOUT=900 readonly TMOUT export TMOUT mesg n 2>/dev/null Not_Reviewed Vuln_Num V-256483 Rule_ID SV-256483r958406_rule Severity medium Rule_Title The Photon operating system must have the sshd SyslogFacility set to "authpriv". Vuln_Discuss Automated monitoring of remote access sessions allows organizations to detect cyberattacks and ensure ongoing compliance with remote access policies by auditing connection activities. Check_Content At the command line, run the following command: # sshd -T|&grep -i SyslogFacility Expected result: syslogfacility AUTHPRIV If there is no output or if the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "SyslogFacility" line is uncommented and set to the following: SyslogFacility AUTHPRIV At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256484 Rule_ID SV-256484r958406_rule Severity medium Rule_Title The Photon operating system must have sshd authentication logging enabled. Vuln_Discuss Automated monitoring of remote access sessions allows organizations to detect cyberattacks and ensure ongoing compliance with remote access policies by auditing connection activities. Shipping sshd authentication events to syslog allows organizations to use their log aggregators to correlate forensic activities among multiple systems. Check_Content At the command line, run the following command: # grep "^authpriv" /etc/rsyslog.conf Expected result should be similar to the following: authpriv.* /var/log/auth.log If "authpriv" is not configured to be logged, this is a finding. Fix_Text Navigate to and open: /etc/rsyslog.conf Add the following line: authpriv.* /var/log/auth.log Note: The path can be substituted for another suitable log destination. At the command line, run the following command: # systemctl restart rsyslog.service Not_Reviewed Vuln_Num V-256485 Rule_ID SV-256485r958406_rule Severity medium Rule_Title The Photon operating system must have the sshd LogLevel set to "INFO". Vuln_Discuss Automated monitoring of remote access sessions allows organizations to detect cyberattacks and ensure ongoing compliance with remote access policies by auditing connection activities. The INFO LogLevel is required, at least, to ensure the capturing of failed login events. Check_Content At the command line, run the following command: # sshd -T|&grep -i LogLevel Expected result: LogLevel INFO If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "LogLevel" line is uncommented and set to the following: LogLevel INFO At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256486 Rule_ID SV-256486r958408_rule Severity low Rule_Title The Photon operating system must configure sshd to use approved encryption algorithms. Vuln_Discuss Without confidentiality protection mechanisms, unauthorized individuals may gain access to sensitive information via a remote access session. OpenSSH on the Photon operating system is compiled with a FIPS-validated cryptographic module. The "FipsMode" setting controls whether this module is initialized and used in FIPS 140-2 mode. Satisfies: SRG-OS-000033-GPOS-00014, SRG-OS-000393-GPOS-00173, SRG-OS-000396-GPOS-00176, SRG-OS-000250-GPOS-00093, SRG-OS-000423-GPOS-00187 Check_Content At the command line, run the following command: # sshd -T|&grep -i FipsMode Expected result: FipsMode yes If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "FipsMode" line is uncommented and set to the following: FipsMode yes At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256487 Rule_ID SV-256487r958412_rule Severity medium Rule_Title The Photon operating system must configure auditd to log to disk. Vuln_Discuss Without establishing what type of events occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Audit record content must be shipped to a central location, but it must also be logged locally. Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019 Check_Content At the command line, run the following command: # grep "^write_logs" /etc/audit/auditd.conf Expected result: write_logs = yes If there is no output, this is not a finding. If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/audit/auditd.conf Ensure the "write_logs" line is uncommented and set to the following: write_logs = yes At the command line, run the following command: # killproc auditd -TERM # systemctl start auditd Not_Reviewed Vuln_Num V-256488 Rule_ID SV-256488r958414_rule Severity medium Rule_Title The Photon operating system must configure auditd to use the correct log format. Vuln_Discuss To compile an accurate risk assessment and provide forensic analysis, it is essential for security personnel to know exact, unfiltered details of the event in question. Check_Content At the command line, run the following command: # grep "^log_format" /etc/audit/auditd.conf Expected result: log_format = RAW If there is no output, this is not a finding. If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/audit/auditd.conf Ensure the "log_format" line is uncommented and set to the following: log_format = RAW At the command line, run the following command: # killproc auditd -TERM # systemctl start auditd Not_Reviewed Vuln_Num V-256489 Rule_ID SV-256489r958422_rule Severity medium Rule_Title The Photon operating system must be configured to audit the execution of privileged functions. Vuln_Discuss Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised information system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing all actions by superusers is one way to detect such misuse and identify the risk from insider threats and the advanced persistent threat. Check_Content At the command line, run the following command: # auditctl -l | grep execve Expected result: -a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -F key=execpriv -a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -F key=execpriv -a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -F key=execpriv -a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -F key=execpriv If the output does not match the expected result, this is a finding. Note: This check depends on the auditd service to be in a running state for accurate results. Enabling the auditd service is done in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following lines: -a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -F key=execpriv -a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -F key=execpriv -a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -F key=execpriv -a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -F key=execpriv At the command line, run the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256490 Rule_ID SV-256490r958422_rule Severity medium Rule_Title The Photon operating system must have the auditd service running. Vuln_Discuss Event outcomes can include indicators of event success or failure and event-specific results (e.g., the security state of the information system after the event occurred). They also provide a means to measure the impact of an event and help authorized personnel to determine the appropriate response. Satisfies: SRG-OS-000042-GPOS-00021, SRG-OS-000062-GPOS-00031, SRG-OS-000255-GPOS-00096, SRG-OS-000363-GPOS-00150, SRG-OS-000365-GPOS-00152, SRG-OS-000445-GPOS-00199, SRG-OS-000446-GPOS-00200, SRG-OS-000461-GPOS-00205, SRG-OS-000467-GPOS-00211, SRG-OS-000465-GPOS-00209, SRG-OS-000474-GPOS-00219, SRG-OS-000475-GPOS-00220 Check_Content At the command line, run the following command: # systemctl status auditd If the service is not running, this is a finding. Fix_Text At the command line, run the following commands: # systemctl enable auditd # systemctl start auditd Not_Reviewed Vuln_Num V-256491 Rule_ID SV-256491r958424_rule Severity medium Rule_Title The Photon operating system audit log must log space limit problems to syslog. Vuln_Discuss It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected. Satisfies: SRG-OS-000046-GPOS-00022, SRG-OS-000344-GPOS-00135 Check_Content At the command line, run the following command: # grep "^space_left_action" /etc/audit/auditd.conf Expected result: space_left_action = SYSLOG If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/audit/auditd.conf Ensure the "space_left_action" line is uncommented and set to the following: space_left_action = SYSLOG At the command line, run the following commands: # killproc auditd -TERM # systemctl start auditd Not_Reviewed Vuln_Num V-256492 Rule_ID SV-256492r1038966_rule Severity medium Rule_Title The Photon operating system audit log must attempt to log audit failures to syslog. Vuln_Discuss It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected. Check_Content At the command line, run the following command: # grep -E "^disk_full_action|^disk_error_action|^admin_space_left_action" /etc/audit/auditd.conf If any of the above parameters are not set to "SYSLOG" or are missing, this is a finding. Fix_Text Navigate to and open: /etc/audit/auditd.conf Ensure the following lines are present, not duplicated, and not commented: disk_full_action = SYSLOG disk_error_action = SYSLOG admin_space_left_action = SYSLOG At the command line, run the following commands: # killproc auditd -TERM # systemctl start auditd Not_Reviewed Vuln_Num V-256493 Rule_ID SV-256493r958434_rule Severity medium Rule_Title The Photon operating system audit log must have correct permissions. Vuln_Discuss Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit operating system activity. Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Check_Content At the command line, run the following command: # (audit_log_file=$(grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//) && if [ -f "${audit_log_file}" ] ; then printf "Log(s) found in "${audit_log_file%/*}":\n"; stat -c "%n permissions are %a" ${audit_log_file%}*; else printf "audit log file(s) not found\n"; fi) If the permissions on any audit log file are more permissive than "0600", this is a finding. Fix_Text At the command line, run the following command: # chmod 0600 <audit log file> Replace <audit log file> with the log files more permissive than 0600. Not_Reviewed Vuln_Num V-256494 Rule_ID SV-256494r958436_rule Severity medium Rule_Title The Photon operating system audit log must be owned by root. Vuln_Discuss Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit operating system activity. Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Check_Content At the command line, run the following command: # (audit_log_file=$(grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//) && if [ -f "${audit_log_file}" ] ; then printf "Log(s) found in "${audit_log_file%/*}":\n"; stat -c "%n is owned by %U" ${audit_log_file%}*; else printf "audit log file(s) not found\n"; fi) If any audit log file is not owned by root, this is a finding. Fix_Text At the command line, run the following command: # chown root:root <audit log file> Replace <audit log file> with the log files not owned by root. Not_Reviewed Vuln_Num V-256495 Rule_ID SV-256495r958438_rule Severity medium Rule_Title The Photon operating system audit log must be group-owned by root. Vuln_Discuss Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit operating system activity. Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Check_Content At the command line, run the following command: # (audit_log_file=$(grep "^log_file" /etc/audit/auditd.conf|sed s/^[^\/]*//) && if [ -f "${audit_log_file}" ] ; then printf "Log(s) found in "${audit_log_file%/*}":\n"; stat -c "%n is group owned by %G" ${audit_log_file%}*; else printf "audit log file(s) not found\n"; fi) If any audit log file is not group owned by root, this is a finding. Fix_Text At the command line, run the following command: # chown root:root <audit log file> Replace <audit log file> with the log files not group owned by root. Not_Reviewed Vuln_Num V-256496 Rule_ID SV-256496r958444_rule Severity medium Rule_Title The Photon operating system must allow only the information system security manager (ISSM) (or individuals or roles appointed by the ISSM) to select which auditable events are to be audited. Vuln_Discuss Without the capability to restrict the roles and individuals that can select which events are audited, unauthorized personnel may be able to prevent the auditing of critical events. Misconfigured audits may degrade the system's performance by overwhelming the audit log. Misconfigured audits may also make it more difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Check_Content At the command line, run the following command: # find /etc/audit/* -type f -exec stat -c "%n permissions are %a" {} $1\; If the permissions of any files are more permissive than "640", this is a finding. Fix_Text At the command line, run the following command: # chmod 640 <file> Replace <file> with any file with incorrect permissions. Not_Reviewed Vuln_Num V-256497 Rule_ID SV-256497r958446_rule Severity medium Rule_Title The Photon operating system must generate audit records when successful/unsuccessful attempts to access privileges occur. Vuln_Discuss Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212 Check_Content At the command line, run the following command: # auditctl -l | grep chmod Expected result: -a always,exit -F arch=b64 -S chmod,fchmod,chown,fchown,fchownat,fchmodat -F auid>=1000 -F auid!=4294967295 -F key=perm_mod -a always,exit -F arch=b64 -S chmod,fchmod,chown,fchown,lchown,setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr,fchownat,fchmodat -F key=perm_mod -a always,exit -F arch=b32 -S chmod,fchmod,fchown,chown,fchownat,fchmodat -F auid>=1000 -F auid!=4294967295 -F key=perm_mod -a always,exit -F arch=b32 -S chmod,lchown,fchmod,fchown,chown,setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr,fchownat,fchmodat -F key=perm_mod If the output does not match the expected result, this is a finding. Note: The auid!= parameter may display as 4294967295 or -1, which are equivalent. Note: This check depends on the auditd service to be in a running state for accurate results. The auditd service is enabled in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following lines: -a always,exit -F arch=b64 -S chmod,fchmod,chown,fchown,fchownat,fchmodat -F auid>=1000 -F auid!=4294967295 -F key=perm_mod -a always,exit -F arch=b64 -S chmod,fchmod,chown,fchown,lchown,setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr,fchownat,fchmodat -F key=perm_mod -a always,exit -F arch=b32 -S chmod,fchmod,fchown,chown,fchownat,fchmodat -F auid>=1000 -F auid!=4294967295 -F key=perm_mod -a always,exit -F arch=b32 -S chmod,lchown,fchmod,fchown,chown,setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr,fchownat,fchmodat -F key=perm_mod At the command line, run the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256498 Rule_ID SV-256498r982195_rule Severity medium Rule_Title The Photon operating system must enforce password complexity by requiring that at least one uppercase character be used. Vuln_Discuss Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Check_Content At the command line, run the following command: # grep pam_cracklib /etc/pam.d/system-password|grep --color=always "ucredit=.." Expected result: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root If the output does not include ucredit= <= -1, this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-password Add the following, replacing any existing "pam_cracklib.so" line: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256499 Rule_ID SV-256499r982196_rule Severity medium Rule_Title The Photon operating system must enforce password complexity by requiring that at least one lowercase character be used. Vuln_Discuss Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Check_Content At the command line, run the following command: # grep pam_cracklib /etc/pam.d/system-password|grep --color=always "lcredit=.." Expected result: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root If the output does not include lcredit= <= -1, this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-password Add the following, replacing any existing "pam_cracklib.so" line: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256500 Rule_ID SV-256500r982197_rule Severity medium Rule_Title The Photon operating system must enforce password complexity by requiring that at least one numeric character be used. Vuln_Discuss Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Check_Content At the command line, run the following command: # grep pam_cracklib /etc/pam.d/system-password|grep --color=always "dcredit=.." Expected result: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root If the output does not include dcredit= <= -1, this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-password Add the following, replacing any existing "pam_cracklib.so" line: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256501 Rule_ID SV-256501r982198_rule Severity medium Rule_Title The Photon operating system must require that new passwords are at least four characters different from the old password. Vuln_Discuss Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Check_Content At the command line, run the following command: # grep pam_cracklib /etc/pam.d/system-password|grep --color=always "difok=." Expected result: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root If the output does not include difok >= 4, this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-password Add the following, replacing any existing "pam_cracklib.so" line: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256502 Rule_ID SV-256502r982199_rule Severity medium Rule_Title The Photon operating system must store only encrypted representations of passwords. Vuln_Discuss Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Check_Content At the command line, run the following command: # grep SHA512 /etc/login.defs|grep -v "#" Expected result: ENCRYPT_METHOD SHA512 If there is no output or if the output does match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/login.defs Add or replace the ENCRYPT_METHOD line as follows: ENCRYPT_METHOD SHA512 Not_Reviewed Vuln_Num V-256503 Rule_ID SV-256503r987796_rule Severity medium Rule_Title The Photon operating system must use an OpenSSH server version that does not support protocol 1. Vuln_Discuss A replay attack may enable an unauthorized user to gain access to the operating system. Authentication sessions between the authenticator and the operating system validating the user credentials must not be vulnerable to a replay attack. An authentication process resists replay attacks if it is impractical to achieve a successful authentication by recording and replaying a previous authentication message. A privileged account is any information system account with authorizations of a privileged user. Techniques used to address this include protocols using nonces (e.g., numbers generated for a specific one-time use) or challenges (e.g., TLS, WS_Security). Additional techniques include time-synchronous or challenge-response one-time authenticators. Satisfies: SRG-OS-000074-GPOS-00042, SRG-OS-000112-GPOS-00057, SRG-OS-000113-GPOS-00058, SRG-OS-000120-GPOS-00061, SRG-OS-000125-GPOS-00065, SRG-OS-000395-GPOS-00175, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190 Check_Content At the command line, run the following command: # rpm -qa|grep openssh If there is no output or openssh is not >= version 7.4, this is a finding. Fix_Text Installing openssh manually is not supported by VMware for appliances. Revert to a previous backup or redeploy the appliance. Not_Reviewed Vuln_Num V-256504 Rule_ID SV-256504r982188_rule Severity medium Rule_Title The Photon operating system must be configured so that passwords for new users are restricted to a 24-hour minimum lifetime. Vuln_Discuss Enforcing a minimum password lifetime helps to prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse. Check_Content At the command line, run the following command: # grep "^PASS_MIN_DAYS" /etc/login.defs If "PASS_MIN_DAYS" is not set to "1", this is a finding. Fix_Text Navigate to and open: /etc/login.defs Modify the "PASS_MIN_DAYS" line to the following: PASS_MIN_DAYS 1 Not_Reviewed Vuln_Num V-256505 Rule_ID SV-256505r1038967_rule Severity medium Rule_Title The Photon operating system must be configured so that passwords for new users are restricted to a 90-day maximum lifetime. Vuln_Discuss Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If the operating system does not limit the lifetime of passwords and force users to change their passwords, there is the risk that the operating system passwords could be compromised. Check_Content At the command line, run the following command: # grep "^PASS_MAX_DAYS" /etc/login.defs If the value of "PASS_MAX_DAYS" is greater than "90", this is a finding. Fix_Text Navigate to and open: /etc/login.def Modify the "PASS_MAX_DAYS" line to the following: PASS_MAX_DAYS 90 Not_Reviewed Vuln_Num V-256506 Rule_ID SV-256506r982201_rule Severity medium Rule_Title The Photon operating system must prohibit password reuse for a minimum of five generations. Vuln_Discuss Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. If the information system or application allows the user to consecutively reuse their password when that password has exceeded its defined lifetime, the result is a password that is not changed per policy requirements. Check_Content At the command line, run the following command: # grep pam_pwhistory /etc/pam.d/system-password|grep --color=always "remember=." Expected result: password requisite pam_pwhistory.so enforce_for_root use_authtok remember=5 retry=3 If the output does not include the "remember=5" setting as shown in the expected result, this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-password Add the following line after the "password requisite pam_cracklib.so" statement: password requisite pam_pwhistory.so enforce_for_root use_authtok remember=5 retry=3 Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256507 Rule_ID SV-256507r982202_rule Severity medium Rule_Title The Photon operating system must enforce a minimum eight-character password length. Vuln_Discuss The shorter the password, the lower the number of possible combinations that need to be tested before the password is compromised. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. Use of more characters in a password helps to exponentially increase the time and/or resources required to compromise the password. Check_Content At the command line, run the following command: # grep pam_cracklib /etc/pam.d/system-password|grep --color=always "minlen=.." Example result: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root If the output does not include minlen >= 8, this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-password Add the following, replacing any existing "pam_cracklib.so" line: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256508 Rule_ID SV-256508r958472_rule Severity high Rule_Title The Photon operating system must require authentication upon booting into single-user and maintenance modes. Vuln_Discuss If the system does not require authentication before it boots into single-user mode, anyone with console access to the system can trivially access all files on the system. GRUB2 is the boot loader for Photon OS and can be configured to require a password to boot into single-user mode or make modifications to the boot menu. Note: Photon does not support building grub changes via grub2-mkconfig. Check_Content At the command line, run the following command: # grep -i ^password_pbkdf2 /boot/grub2/grub.cfg If there is not output, this is a finding. If the output does not begin with "password_pbkdf2 root", this is a finding. Fix_Text At the command line, run the following command: # grub2-mkpasswd-pbkdf2 Enter a secure password and ensure this password is stored for break-glass situations. The vCenter root account cannot be recovered without knowing this separate password. Copy the resulting encrypted string. An example string is below: grub.pbkdf2.sha512.10000.983A13DF3C51BB2B5130F0B86DDBF0DEA1AAF766BD1F16B7840F79CE3E35494C4B99F505C99C150071E563DF1D7FE1F45456D5960C4C79DAB6C49298B02A5558.5B2C49E12D43CC5A876F6738462DE4EFC24939D4BE486CDB72CFBCD87FDE93FBAFCB817E01B90F23E53C2502C3230502BC3113BE4F80B0AFC0EE956E735F7F86 Navigate to and open: /boot/grub2/grub.cfg Find the line that begins with "set rootpartition". Below this line, paste the following on its own line: set superusers="root" Below this, paste the following, substituting the encrypted string from the steps above: password_pbkdf2 root <YOUR-LONG-STRING-FROM-ABOVE> Photon ships with one menuentry block by default. Copy that entire block and paste it right below itself. Example: menuentry "Photon" { linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0 if [ "$photon_initrd" ]; then initrd "/"$photon_initrd fi } menuentry "Photon" { linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0 if [ "$photon_initrd" ]; then initrd "/"$photon_initrd fi } Modify the first menuentry block to add the "--unrestricted" option as follows: menuentry "Photon" --unrestricted { Modify the second menuentry block to add the allowed user as follows: menuentry "Recover Photon" --users root { This concludes the fix. To verify, here is an example grub.cfg snippet: ... set rootpartition=PARTUUID=326e5b0f-42fb-471a-8209-18964c4a2ed3 set superusers="root" password_pbkdf2 root grub.pbkdf2.sha512.10000.983A13DF3C51BB2B5130F0B86DDBF0DEA1AAF766BD1F16B7840F79CE3E35494C4B99F505C99C150071E563DF1D7FE1F45456D5960C4C79DAB6C49298B02A5558.5B2C49E12D43CC5A876F6738462DE4EFC24939D4BE486CDB72CFBCD87FDE93FBAFCB817E01B90F23E53C2502C3230502BC3113BE4F80B0AFC0EE956E735F7F86 menuentry "Photon" --unrestricted { linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0 if [ "$photon_initrd" ]; then initrd "/"$photon_initrd fi } menuentry "Recover Photon" --users root { linux "/"$photon_linux root=$rootpartition net.ifnames=0 $photon_cmdline coredump_filter=0x37 consoleblank=0 if [ "$photon_initrd" ]; then initrd "/"$photon_initrd fi } Not_Reviewed Vuln_Num V-256509 Rule_ID SV-256509r958480_rule Severity medium Rule_Title The Photon operating system must disable the loading of unnecessary kernel modules. Vuln_Discuss To support the requirements and principles of least functionality, the operating system must provide only essential capabilities and limit the use of modules, protocols, and/or services to only those required for the proper functioning of the product. Satisfies: SRG-OS-000096-GPOS-00050, SRG-OS-000114-GPOS-00059 Check_Content At the command line, run the following command: # modprobe --showconfig | grep "^install" | grep "/bin" Expected result: install sctp /bin/false install dccp /bin/false install dccp_ipv4 /bin/false install dccp_ipv6 /bin/false install ipx /bin/false install appletalk /bin/false install decnet /bin/false install rds /bin/false install tipc /bin/false install bluetooth /bin/false install usb_storage /bin/false install ieee1394 /bin/false install cramfs /bin/false install freevxfs /bin/false install jffs2 /bin/false install hfs /bin/false install hfsplus /bin/false install squashfs /bin/false install udf /bin/false The output may include other statements outside of the expected result. If the output does not include at least every statement in the expected result, this is a finding. Fix_Text Navigate to and open: /etc/modprobe.d/modprobe.conf Set the contents as follows: install sctp /bin/false install dccp /bin/false install dccp_ipv4 /bin/false install dccp_ipv6 /bin/false install ipx /bin/false install appletalk /bin/false install decnet /bin/false install rds /bin/false install tipc /bin/false install bluetooth /bin/false install usb_storage /bin/false install ieee1394 /bin/false install cramfs /bin/false install freevxfs /bin/false install jffs2 /bin/false install hfs /bin/false install hfsplus /bin/false install squashfs /bin/false install udf /bin/false Not_Reviewed Vuln_Num V-256510 Rule_ID SV-256510r958482_rule Severity medium Rule_Title The Photon operating system must not have duplicate User IDs (UIDs). Vuln_Discuss To ensure accountability and prevent unauthenticated access, organizational users must be uniquely identified and authenticated to prevent potential misuse and provide for nonrepudiation. Check_Content At the command line, run the following command: # awk -F ":" 'list[$3]++{print $1, $3}' /etc/passwd If any lines are returned, this is a finding. Fix_Text Navigate to and open: /etc/passwd Configure each user account that has a duplicate UID with a unique UID. Not_Reviewed Vuln_Num V-256511 Rule_ID SV-256511r982189_rule Severity medium Rule_Title The Photon operating system must disable new accounts immediately upon password expiration. Vuln_Discuss Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained. Disabling inactive accounts ensures accounts that may not have been responsibly removed are not available to attackers who may have compromised their credentials. Check_Content At the command line, run the following command: # grep INACTIVE /etc/default/useradd Expected result: INACTIVE=0 If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/default/useradd Remove an existing "INACTIVE" line and add the following line: INACTIVE=0 Not_Reviewed Vuln_Num V-256512 Rule_ID SV-256512r958528_rule Severity medium Rule_Title The Photon operating system must use Transmission Control Protocol (TCP) syncookies. Vuln_Discuss A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected and enables the system to continue servicing valid connection requests. Satisfies: SRG-OS-000142-GPOS-00071, SRG-OS-000420-GPOS-00186 Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern tcp_syncookies Expected result: net.ipv4.tcp_syncookies = 1 If the output does not match the expected result, this is a finding. Fix_Text At the command line, run the following commands: # sed -i -e "/^net.ipv4.tcp_syncookies/d" /etc/sysctl.conf # echo net.ipv4.tcp_syncookies=1>>/etc/sysctl.conf # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256513 Rule_ID SV-256513r970703_rule Severity medium Rule_Title The Photon operating system must configure sshd to disconnect idle Secure Shell (SSH) sessions. Vuln_Discuss Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on a console or console port that has been left unattended. Check_Content At the command line, run the following command: # sshd -T|&grep -i ClientAliveInterval Expected result: ClientAliveInterval 900 If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "ClientAliveInterval" line is uncommented and set to the following: ClientAliveInterval 900 At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256514 Rule_ID SV-256514r970703_rule Severity medium Rule_Title The Photon operating system must configure sshd to disconnect idle Secure Shell (SSH) sessions. Vuln_Discuss Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on a console or console port that has been left unattended. Check_Content At the command line, run the following command: # sshd -T|&grep -i ClientAliveCountMax Expected result: ClientAliveCountMax 0 If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "ClientAliveCountMax" line is uncommented and set to the following: ClientAliveCountMax 0 At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256515 Rule_ID SV-256515r958566_rule Severity medium Rule_Title The Photon operating system "/var/log" directory must be owned by root. Vuln_Discuss Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state and can provide sensitive information to an unprivileged attacker. Check_Content At the command line, run the following command: # stat -c "%n is owned by %U and group owned by %G" /var/log If the "/var/log directory" is not owned by root, this is a finding. Fix_Text At the command line, run the following command: # chown root:root /var/log Not_Reviewed Vuln_Num V-256516 Rule_ID SV-256516r958566_rule Severity medium Rule_Title The Photon operating system messages file must have the correct ownership and file permissions. Vuln_Discuss Only authorized personnel should be aware of errors and the details of the errors. Error messages are an indicator of an organization's operational state and can provide sensitive information to an unprivileged attacker. Check_Content At the command line, run the following command: # stat -c "%n is owned by %U and group owned by %G with %a permissions" /var/log/messages If the "/var/log/messages" directory is not owned by root or not group owned by root, or the file permissions are more permission than "640", this is a finding. Fix_Text At the command line, run the following commands: # chown root:root /var/log/messages # chmod 0640 /var/log/messages Not_Reviewed Vuln_Num V-256517 Rule_ID SV-256517r991551_rule Severity medium Rule_Title The Photon operating system must audit all account modifications. Vuln_Discuss Once an attacker establishes access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to modify an existing account. Auditing account modification actions provides logging that can be used for forensic purposes. Check_Content At the command line, run the following command: # auditctl -l | grep -E "(usermod|groupmod)" Expected result: -w /usr/sbin/usermod -p x -k usermod -w /usr/sbin/groupmod -p x -k groupmod If the output does not match the expected result, this is a finding. Note: This check depends on the auditd service to be in a running state for accurate results. The auditd service is enabled in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following lines: -w /usr/sbin/usermod -p x -k usermod -w /usr/sbin/groupmod -p x -k groupmod At the command line, run the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256518 Rule_ID SV-256518r991551_rule Severity medium Rule_Title The Photon operating system must audit all account modifications. Vuln_Discuss Once an attacker establishes access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to modify an existing account. Auditing account modification actions provides logging that can be used for forensic purposes. Satisfies: SRG-OS-000239-GPOS-00089, SRG-OS-000303-GPOS-00120 Check_Content At the command line, run the following command: # auditctl -l | grep -E "(/etc/passwd|/etc/shadow|/etc/group|/etc/gshadow)" Expected result: -w /etc/passwd -p wa -k passwd -w /etc/shadow -p wa -k shadow -w /etc/group -p wa -k group -w /etc/gshadow -p wa -k gshadow If the output does not match the expected result, this is a finding. Note: This check depends on the auditd service to be in a running state for accurate results. The auditd service is enabled in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following lines: -w /etc/passwd -p wa -k passwd -w /etc/shadow -p wa -k shadow -w /etc/group -p wa -k group -w /etc/gshadow -p wa -k gshadow At the command line, run the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256519 Rule_ID SV-256519r991552_rule Severity medium Rule_Title The Photon operating system must audit all account disabling actions. Vuln_Discuss When operating system accounts are disabled, user accessibility is affected. Accounts are used for identifying individual users or operating system processes. To detect and respond to events affecting user accessibility and system processing, operating systems must audit account disabling actions. Check_Content At the command line, run the following command: # auditctl -l | grep "w /usr/bin/passwd" Expected result: -w /usr/bin/passwd -p x -k passwd If the output does not match the expected result, this is a finding. Note: This check depends on the auditd service to be in a running state for accurate results. The auditd service is enabled in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following lines: -w /usr/bin/passwd -p x -k passwd At the command line, run the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256520 Rule_ID SV-256520r991553_rule Severity medium Rule_Title The Photon operating system must audit all account removal actions. Vuln_Discuss When operating system accounts are removed, user accessibility is affected. Accounts are used for identifying individual users or operating system processes. To detect and respond to events affecting user accessibility and system processing, operating systems must audit account removal actions. Check_Content At the command line, run the following command: # auditctl -l | grep -E "(userdel|groupdel)" Expected result: -w /usr/sbin/userdel -p x -k userdel -w /usr/sbin/groupdel -p x -k groupdel If the output does not match the expected result, this is a finding. Note: This check depends on the auditd service to be in a running state for accurate results. Enabling the auditd service is done in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following lines: -w /usr/sbin/userdel -p x -k userdel -w /usr/sbin/groupdel -p x -k groupdel At the command line, run the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256521 Rule_ID SV-256521r991555_rule Severity medium Rule_Title The Photon operating system must initiate auditing as part of the boot process. Vuln_Discuss Each process on the system carries an "auditable" flag, which indicates whether its activities can be audited. Although auditd takes care of enabling this for all processes that launch after it starts, adding the kernel argument ensures the flag is set at boot for every process on the system. This includes processes created before auditd starts. Check_Content At the command line, run the following command: # grep "audit=1" /proc/cmdline If no results are returned, this is a finding. Fix_Text Navigate to and open: /boot/grub2/grub.cfg Locate the boot command line arguments. An example follows: linux /$photon_linux root=$rootpartition $photon_cmdline $systemd_cmdline Add "audit=1" to the end of the line so it reads as follows: linux /$photon_linux root=$rootpartition $photon_cmdline $systemd_cmdline audit=1 Note: Do not copy/paste in this example argument line. This may change in future releases. Find the similar line and append "audit=1" to it. Reboot the system for the change to take effect. Not_Reviewed Vuln_Num V-256522 Rule_ID SV-256522r991557_rule Severity medium Rule_Title The Photon operating system audit files and directories must have correct permissions. Vuln_Discuss Protecting audit information includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operations on audit information. Check_Content At the command line, run the following command: # stat -c "%n is owned by %U and group owned by %G" /etc/audit/auditd.conf If "auditd.conf" is not owned by root and group owned by root, this is a finding. Fix_Text At the command line, run the following command: # chown root:root /etc/audit/auditd.conf Not_Reviewed Vuln_Num V-256523 Rule_ID SV-256523r991558_rule Severity medium Rule_Title The Photon operating system must protect audit tools from unauthorized modification and deletion. Vuln_Discuss Protecting audit information includes identifying and protecting the tools used to view and manipulate log data. Therefore, protecting audit tools is necessary to prevent unauthorized operations on audit information. Satisfies: SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099 Check_Content At the command line, run the following command: # stat -c "%n is owned by %U and group owned by %G and permissions are %a" /usr/sbin/auditctl /usr/sbin/auditd /usr/sbin/aureport /usr/sbin/ausearch /usr/sbin/autrace If any file is not owned by root or group-owned by root or permissions are more permissive than "750", this is a finding. Fix_Text At the command line, run the following command for each file returned for user and group ownership: # chown root:root <file> At the command line, run the following command for each file returned for file permissions: # chmod 750 <file> Not_Reviewed Vuln_Num V-256524 Rule_ID SV-256524r991561_rule Severity medium Rule_Title The Photon operating system must enforce password complexity by requiring that at least one special character be used. Vuln_Discuss Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Check_Content At the command line, run the following command: # grep pam_cracklib /etc/pam.d/system-password|grep --color=always "ocredit=.." Expected result: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root If the output does not include ocredit= <= -1, this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-password Add the following, replacing any existing "pam_cracklib.so" line: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256525 Rule_ID SV-256525r991567_rule Severity medium Rule_Title The Photon operating system package files must not be modified. Vuln_Discuss Protecting the integrity of the tools used for auditing purposes is a critical step toward ensuring the integrity of audit information. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity. Without confidence in the integrity of the auditing system and tools, the information it provides cannot be trusted. Check_Content Use the verification capability of rpm to check the MD5 hashes of the audit files on disk versus the expected ones from the installation package. At the command line, run the following command: # rpm -V audit | grep "^..5" | grep -v "^...........c" If there is any output, this is a finding. Fix_Text If the audit system binaries have been altered, the system must be taken offline and the information system security manager (ISSM) notified immediately. Reinstalling the audit tools is not supported. The appliance should be restored from a backup or redeployed once the root cause is remediated. Not_Reviewed Vuln_Num V-256526 Rule_ID SV-256526r958732_rule Severity medium Rule_Title The Photon operating system must audit the execution of privileged functions. Vuln_Discuss Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised information system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider threats and the advanced persistent threat. Satisfies: SRG-OS-000327-GPOS-00127, SRG-OS-000471-GPOS-00215 Check_Content At the command line, run the following command to obtain a list of setuid files: # find / -xdev -path /var/lib/containerd -prune -o \( -perm -4000 -type f -o -perm -2000 \) -type f -print | sort Run the following command for each setuid file found in the first command: # auditctl -l | grep <setuid_path> Replace <setuid_path> with each path found in the first command. If each <setuid_path> does not have a corresponding line in the audit rules, this is a finding. A typical corresponding line will look like the following: -a always,exit -S all -F path=<setuid_path> -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged Note: The auid!= parameter may display as 4294967295 or -1, which are equivalent. Note: This check depends on the auditd service to be in a running state for accurate results. The auditd service is enabled in control PHTN-30-000013. Fix_Text At the command line, run the following command to obtain a list of setuid files: # find / -xdev -perm -4000 -type f -o -perm -2000 -type f | sort Execute the following for each setuid file found in the first command that does not have a corresponding line in the audit rules: Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following line: -a always,exit -F path=<setuid_path> -F perm=x -F auid>=1000 -F auid!=4294967295 -F key=privileged Execute the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256527 Rule_ID SV-256527r958752_rule Severity medium Rule_Title The Photon operating system must configure auditd to keep five rotated log files. Vuln_Discuss Audit logs are most useful when accessible by date, rather than size. This can be accomplished through a combination of an audit log rotation cron job, setting a reasonable number of logs to keep, and configuring auditd to not rotate the logs on its own. This ensures audit logs are accessible to the information system security officer (ISSO) in the event of a central log processing failure. Check_Content At the command line, run the following command: # grep "^num_logs" /etc/audit/auditd.conf Expected result: num_logs = 5 If the output of the command does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/audit/auditd.conf Add or change the "num_logs" line as follows: num_logs = 5 At the command line, run the following commands: # killproc auditd -TERM # systemctl start auditd Not_Reviewed Vuln_Num V-256528 Rule_ID SV-256528r958752_rule Severity medium Rule_Title The Photon operating system must configure auditd to keep logging in the event max log file size is reached. Vuln_Discuss Audit logs are most useful when accessible by date, rather than size. This can be accomplished through a combination of an audit log rotation cron job, setting a reasonable number of logs to keep, and configuring auditd to not rotate the logs on its own. This ensures audit logs are accessible to the information system security officer (ISSO) in the event of a central log processing failure. If another solution is not used to rotate auditd logs, auditd can be configured to rotate logs. Check_Content At the command line, run the following command: # grep "^max_log_file_action" /etc/audit/auditd.conf Example result: max_log_file_action = IGNORE If logs are rotated outside of auditd with a tool such as logrotated, and this setting is not set to "IGNORE", this is a finding. If logs are NOT rotated outside of auditd, and this setting is not set to "ROTATE", this is a finding. Fix_Text Navigate to and open: /etc/audit/auditd.conf Add or change the "max_log_file_action" line as follows: max_log_file_action = IGNORE Note: This can also be set to "ROTATE" if another tool is not used to rotate auditd logs. At the command line, run the following commands: # killproc auditd -TERM # systemctl start auditd Not_Reviewed Vuln_Num V-256529 Rule_ID SV-256529r971542_rule Severity medium Rule_Title The Photon operating system must configure auditd to log space limit problems to syslog. Vuln_Discuss If security personnel are not notified immediately when storage volume reaches 75 percent utilization, they are unable to plan for audit record storage capacity expansion. Check_Content At the command line, run the following command: # grep "^space_left " /etc/audit/auditd.conf Expected result: space_left = 75 If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/audit/auditd.conf Ensure the "space_left" line is uncommented and set to the following: space_left = 75 At the command line, run the following commands: # killproc auditd -TERM # systemctl start auditd Not_Reviewed Vuln_Num V-256530 Rule_ID SV-256530r982212_rule Severity medium Rule_Title The Photon operating system RPM package management tool must cryptographically verify the authenticity of all software packages during installation. Vuln_Discuss Installation of any nontrusted software, patches, service packs, device drivers, or operating system components can significantly affect the overall security of the operating system. Ensuring all packages' cryptographic signatures are valid prior to installation ensures the provenance of the software and protects against malicious tampering. Check_Content At the command line, run the following command: # grep -s nosignature /usr/lib/rpm/rpmrc /etc/rpmrc ~root/.rpmrc If the command returns any output, this is a finding. Fix_Text Open the file containing "nosignature" with a text editor and remove the option. Not_Reviewed Vuln_Num V-256531 Rule_ID SV-256531r982212_rule Severity medium Rule_Title The Photon operating system RPM package management tool must cryptographically verify the authenticity of all software packages during installation. Vuln_Discuss Installation of any nontrusted software, patches, service packs, device drivers, or operating system components can significantly affect the overall security of the operating system. Cryptographically verifying the authenticity of all software packages during installation ensures the software has not been tampered with and has been provided by a trusted vendor. Check_Content At the command line, run the following command: # grep "^gpgcheck" /etc/tdnf/tdnf.conf If "gpgcheck" is not set to "1", this is a finding. Fix_Text Navigate to and open: /etc/tdnf/tdnf.conf Remove any existing "gpgcheck" setting and add the following line: gpgcheck=1 Not_Reviewed Vuln_Num V-256532 Rule_ID SV-256532r982212_rule Severity medium Rule_Title The  Photon operating system YUM repository must cryptographically verify the authenticity of all software packages during installation. Vuln_Discuss Installation of any nontrusted software, patches, service packs, device drivers, or operating system components can significantly affect the overall security of the operating system. Cryptographically verifying the authenticity of all software packages during installation ensures the software has not been tampered with and has been provided by a trusted vendor. Check_Content At the command line, run the following command: # grep gpgcheck /etc/yum.repos.d/* If "gpgcheck" is not set to "1" in any returned file, this is a finding. Fix_Text Open the file where "gpgcheck" is not set to "1" with a text editor. Remove any existing "gpgcheck" setting and add the following line at the end of the file: gpgcheck=1 Not_Reviewed Vuln_Num V-256533 Rule_ID SV-256533r1050789_rule Severity medium Rule_Title The Photon operating system must require users to reauthenticate for privilege escalation. Vuln_Discuss Without reauthentication, users may access resources or perform tasks for which they do not have authorization. When operating systems provide the capability to escalate a functional capability, it is critical the user reauthenticate. Satisfies: SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158 Check_Content At the command line, run the following commands: # grep -ihs nopasswd /etc/sudoers /etc/sudoers.d/*|grep -v "^#"|grep -v "^%"|awk '{print $1}' # awk -F: '($2 != "x" && $2 != "!") {print $1}' /etc/shadow If any account listed in the first output is also listed in the second output and is not documented, this is a finding. Fix_Text Check the configuration of the "/etc/sudoers" and "/etc/sudoers.d/*" files with the following command: # visudo OR # visudo -f /etc/sudoers.d/<file name> Remove any occurrences of "NOPASSWD" tags associated with user accounts with a password hash. Not_Reviewed Vuln_Num V-256534 Rule_ID SV-256534r958850_rule Severity low Rule_Title The Photon operating system must configure sshd to use FIPS 140-2 ciphers. Vuln_Discuss Privileged access contains control and configuration information and is particularly sensitive, so additional protections are necessary. This is maintained by using cryptographic mechanisms such as encryption to protect confidentiality. Nonlocal maintenance and diagnostic activities are conducted by individuals communicating through an external network (e.g., the internet) or internal network. Local maintenance and diagnostic activities are carried out by individuals physically present at the information system or information system component and not communicating across a network connection. This requirement applies to hardware/software diagnostic test equipment or tools. It does not cover hardware/software components that may support information system maintenance, yet are a part of the system (e.g., the software implementing "ping," "ls," "ipconfig," or the hardware and software implementing the monitoring port of an Ethernet switch). The operating system can meet this requirement by leveraging a cryptographic module. Satisfies: SRG-OS-000394-GPOS-00174, SRG-OS-000424-GPOS-00188 Check_Content At the command line, run the following command: # sshd -T|&grep -i Ciphers Expected result: ciphers aes128-ctr,aes128-gcm@openssh.com,aes192-ctr,aes256-gcm@openssh.com,aes256-ctr If the output matches the ciphers in the expected result or a subset thereof, this is not a finding. If the ciphers in the output contain any ciphers not listed in the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "Ciphers" line is uncommented and set to the following: Ciphers aes128-ctr,aes128-gcm@openssh.com,aes192-ctr,aes256-gcm@openssh.com,aes256-ctr At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256535 Rule_ID SV-256535r958928_rule Severity medium Rule_Title The Photon operating system must implement address space layout randomization (ASLR) to protect its memory from unauthorized code execution. Vuln_Discuss ASLR makes it more difficult for an attacker to predict the location of attack code they have introduced into a process's address space during an attempt at exploitation. ASLR also makes it more difficult for an attacker to know the location of existing code to repurpose it using return-oriented programming (ROP) techniques. Check_Content At the command line, run the following command: # cat /proc/sys/kernel/randomize_va_space If the value of "randomize_va_space" is not "2", this is a finding. Fix_Text Navigate to and open: /etc/sysctl.d/50-security-hardening.conf Ensure the "randomize_va_space" is uncommented and set to the following: kernel.randomize_va_space=2 At the command line, run the following command: # sysctl --system Not_Reviewed Vuln_Num V-256536 Rule_ID SV-256536r958936_rule Severity medium Rule_Title The Photon operating system must remove all software components after updated versions have been installed. Vuln_Discuss Previous versions of software components that are not removed from the information system after updates have been installed may be exploited by adversaries. Some information technology products may remove older versions of software automatically from the information system. Check_Content At the command line, run the following command: # grep -i "^clean_requirements_on_remove" /etc/tdnf/tdnf.conf Expected result: clean_requirements_on_remove=true If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/tdnf/tdnf.conf Remove any existing "clean_requirements_on_remove" line and ensure the following line is present: clean_requirements_on_remove=true Not_Reviewed Vuln_Num V-256537 Rule_ID SV-256537r991570_rule Severity medium Rule_Title The Photon operating system must generate audit records when the sudo command is used. Vuln_Discuss Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000458-GPOS-00203, SRG-OS-000463-GPOS-00207 Check_Content At the command line, run the following command: # auditctl -l | grep sudo Expected result: -a always,exit -S all -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged If the output does not match the expected result, this is a finding. Note: The auid!= parameter may display as 4294967295 or -1, which are equivalent. Note: This check depends on the auditd service to be in a running state for accurate results. The auditd service is enabled in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following line: -a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=4294967295 -F key=privileged Execute the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256538 Rule_ID SV-256538r991578_rule Severity medium Rule_Title The Photon operating system must generate audit records when successful/unsuccessful logon attempts occur. Vuln_Discuss Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000470-GPOS-00214, SRG-OS-000472-GPOS-00217, SRG-OS-000473-GPOS-00218 Check_Content At the command line, run the following command: # auditctl -l | grep -E "faillog|lastlog|tallylog" Expected result: -w /var/log/faillog -p wa -w /var/log/lastlog -p wa -w /var/log/tallylog -p wa If the output does not match the expected result, this is a finding. Note: This check depends on the auditd service to be in a running state for accurate results. The auditd service is enabled in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following lines: -w /var/log/faillog -p wa -w /var/log/lastlog -p wa -w /var/log/tallylog -p wa Execute the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256539 Rule_ID SV-256539r991580_rule Severity medium Rule_Title The Photon operating system must audit the "insmod" module. Vuln_Discuss Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Satisfies: SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222 Check_Content At the command line, run the following command: # auditctl -l | grep "/sbin/insmod" Expected result: -w /sbin/insmod -p x If the output does not match the expected result, this is a finding. Note: This check depends on the auditd service to be in a running state for accurate results. The auditd service is enabled in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following lines: -w /sbin/insmod -p x Execute the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256540 Rule_ID SV-256540r991585_rule Severity medium Rule_Title The Photon operating system auditd service must generate audit records for all account creations, modifications, disabling, and termination events. Vuln_Discuss Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). Check_Content At the command line, run the following command: # auditctl -l | grep -E /etc/security/opasswd If any of these are not listed with a permissions filter of at least "w", this is a finding. Note: This check depends on the auditd service to be in a running state for accurate results. The auditd service is enabled in control PHTN-30-000013. Fix_Text Navigate to and open: /etc/audit/rules.d/audit.STIG.rules Add the following line: -w /etc/security/opasswd -p wa -k opasswd Execute the following command to load the new audit rules: # /sbin/augenrules --load Note: A new "audit.STIG.rules" file is provided for placement in "/etc/audit/rules.d" that contains all rules needed for auditd. Note: An older "audit.STIG.rules" may exist if the file exists and references older "GEN" SRG IDs. This file can be removed and replaced as necessary with an updated one. Not_Reviewed Vuln_Num V-256541 Rule_ID SV-256541r991587_rule Severity medium Rule_Title The Photon operating system must use the "pam_cracklib" module. Vuln_Discuss If the operating system allows the user to select passwords based on dictionary words, this increases the chances of password compromise by increasing the opportunity for successful guesses and brute-force attacks. Check_Content At the command line, run the following command: # grep pam_cracklib /etc/pam.d/system-password If the output does not return at least "password requisite pam_cracklib.so", this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-password Add the following, replacing any existing "pam_cracklib.so" line: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256542 Rule_ID SV-256542r991588_rule Severity medium Rule_Title The Photon operating system must set the "FAIL_DELAY" parameter. Vuln_Discuss Limiting the number of logon attempts over a certain time interval reduces the chances that an unauthorized user may gain access to an account. Check_Content At the command line, run the following command: # grep FAIL_DELAY /etc/login.defs Expected result: FAIL_DELAY 4 If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/login.defs Add the following line after the last auth statement: FAIL_DELAY 4 Not_Reviewed Vuln_Num V-256543 Rule_ID SV-256543r991588_rule Severity medium Rule_Title The Photon operating system must enforce a delay of at least four seconds between logon prompts following a failed logon attempt. Vuln_Discuss Limiting the number of logon attempts over a certain time interval reduces the chances that an unauthorized user may gain access to an account. Check_Content At the command line, run the following command: # grep pam_faildelay /etc/pam.d/system-auth|grep --color=always "delay=" Expected result: auth optional pam_faildelay.so delay=4000000 If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-auth Remove any existing "pam_faildelay" line and add the following line at the end of the file: auth optional pam_faildelay.so delay=4000000 Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256544 Rule_ID SV-256544r991589_rule Severity medium Rule_Title The Photon operating system must ensure audit events are flushed to disk at proper intervals. Vuln_Discuss Without setting a balance between performance and ensuring all audit events are written to disk, performance of the system may suffer or the risk of missing audit entries may be too high. Check_Content At the command line, run the following command: # grep -E "freq|flush" /etc/audit/auditd.conf Expected result: flush = INCREMENTAL_ASYNC freq = 50 If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/audit/auditd.conf Ensure the following line is present and any existing "flush" and "freq" settings are removed: flush = INCREMENTAL_ASYNC freq = 50 Not_Reviewed Vuln_Num V-256545 Rule_ID SV-256545r991589_rule Severity medium Rule_Title The Photon operating system must create a home directory for all new local interactive user accounts. Vuln_Discuss If local interactive users are not assigned a valid home directory, there is no place for the storage and control of files they should own. Check_Content At the command line, run the following command: # grep -i "^create_home" /etc/login.defs If there is no output or the output does not equal "CREATE_HOME yes", this is a finding. Fix_Text Navigate to and open: /etc/login.defs Ensure the following is present and any existing "CREATE_HOME" line is removed: CREATE_HOME yes Not_Reviewed Vuln_Num V-256546 Rule_ID SV-256546r991589_rule Severity medium Rule_Title The Photon operating system must disable the debug-shell service. Vuln_Discuss The debug-shell service is intended to diagnose systemd-related boot issues with various "systemctl" commands. Once enabled and following a system reboot, the root shell will be available on tty9. This service must remain disabled until and unless otherwise directed by VMware support. Check_Content At the command line, run the following command: # systemctl status debug-shell.service|grep -E --color=always disabled If the debug-shell service is not disabled, this is a finding. Fix_Text At the command line, run the following commands: # systemctl stop debug-shell.service # systemctl disable debug-shell.service Reboot for changes to take effect. Not_Reviewed Vuln_Num V-256547 Rule_ID SV-256547r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to disallow Generic Security Service Application Program Interface (GSSAPI) authentication. Vuln_Discuss GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through Secure Shell (SSH) exposes the system's GSSAPI to remote hosts, increasing the attack surface of the system. Check_Content At the command line, run the following command: # sshd -T|&grep -i GSSAPIAuthentication Expected result: GSSAPIAuthentication no If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "GSSAPIAuthentication" line is uncommented and set to the following: GSSAPIAuthentication no At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256548 Rule_ID SV-256548r1051424_rule Severity medium Rule_Title The Photon operating system must configure sshd to disable environment processing. Vuln_Discuss Enabling environment processing may enable users to bypass access restrictions in some configurations and must therefore be disabled. Check_Content At the command line, run the following command: #sshd -T|&grep -i PermitUserEnvironment Expected result: PermitUserEnvironment no If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "PermitUserEnvironment" line is uncommented and set to the following: PermitUserEnvironment no At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256549 Rule_ID SV-256549r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to disable X11 forwarding. Vuln_Discuss X11 is an older, insecure graphics forwarding protocol. It is not used by Photon and should be disabled as a general best practice to limit attack surface area and communication channels. Check_Content At the command line, run the following command: # sshd -T|&grep -i X11Forwarding Expected result: X11Forwarding no If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "X11Forwarding" line is uncommented and set to the following: X11Forwarding no At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256550 Rule_ID SV-256550r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to perform strict mode checking of home directory configuration files. Vuln_Discuss If other users have access to modify user-specific Secure Shell (SSH) configuration files, they may be able to log on to the system as another user. Check_Content At the command line, run the following command: # sshd -T|&grep -i StrictModes Expected result: StrictModes yes If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "StrictModes" line is uncommented and set to the following: StrictModes yes At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256551 Rule_ID SV-256551r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to disallow Kerberos authentication. Vuln_Discuss If Kerberos is enabled through Secure Shell (SSH), sshd provides a means of access to the system's Kerberos implementation. Vulnerabilities in the system's Kerberos implementation may then be subject to exploitation. To reduce the attack surface of the system, the Kerberos authentication mechanism within SSH must be disabled. Check_Content At the command line, run the following command: # sshd -T|&grep -i KerberosAuthentication Expected result: KerberosAuthentication no If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "KerberosAuthentication" line is uncommented and set to the following: KerberosAuthentication no At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256552 Rule_ID SV-256552r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to disallow authentication with an empty password. Vuln_Discuss Blank passwords are one of the first things an attacker checks for when probing a system. Even is the user somehow has a blank password on the operating system, sshd must not allow that user to log in. Check_Content At the command line, run the following command: # sshd -T|&grep -i PermitEmptyPasswords Expected result: PermitEmptyPasswords no If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "PermitEmptyPasswords" line is uncommented and set to the following: PermitEmptyPasswords no At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256553 Rule_ID SV-256553r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to disallow compression of the encrypted session stream. Vuln_Discuss If compression is allowed in a Secure Shell (SSH) connection prior to authentication, vulnerabilities in the compression software could result in compromise of the system from an unauthenticated connection. Check_Content At the command line, run the following command: # sshd -T|&grep -i Compression Expected result: Compression no If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "Compression" line is uncommented and set to the following: Compression no At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256554 Rule_ID SV-256554r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to display the last login immediately after authentication. Vuln_Discuss Providing users with feedback on the last time they logged on via Secure Shell (SSH) facilitates user recognition and reporting of unauthorized account use. Check_Content At the command line, run the following command: # sshd -T|&grep -i PrintLastLog Expected result: PrintLastLog yes If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "PrintLastLog" line is uncommented and set to the following: PrintLastLog yes At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256555 Rule_ID SV-256555r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to ignore user-specific trusted hosts lists. Vuln_Discuss Secure Shell (SSH) trust relationships enable trivial lateral spread after a host compromise and therefore must be explicitly disabled. Individual users can have a local list of trusted remote machines, which must also be ignored while disabling host-based authentication generally. Check_Content At the command line, run the following command: # sshd -T|&grep -i IgnoreRhosts Expected result: IgnoreRhosts yes If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "IgnoreRhosts" line is uncommented and set to the following: IgnoreRhosts yes At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256556 Rule_ID SV-256556r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to ignore user-specific "known_host" files. Vuln_Discuss Secure Shell (SSH) trust relationships enable trivial lateral spread after a host compromise and therefore must be explicitly disabled. Individual users can have a local list of trusted remote machines that must also be ignored while disabling host-based authentication generally. Check_Content At the command line, run the following command: # sshd -T|&grep -i IgnoreUserKnownHosts Expected result: IgnoreUserKnownHosts yes If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "IgnoreUserKnownHosts" line is uncommented and set to the following: IgnoreUserKnownHosts yes At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256557 Rule_ID SV-256557r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to limit the number of allowed login attempts per connection. Vuln_Discuss By setting the login attempt limit to a low value, an attacker will be forced to reconnect frequently, which severely limits the speed and effectiveness of brute-force attacks. Check_Content At the command line, run the following command: # sshd -T|&grep -i MaxAuthTries Expected result: MaxAuthTries 6 If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "MaxAuthTries" line is uncommented and set to the following: MaxAuthTries 6 At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256558 Rule_ID SV-256558r991589_rule Severity medium Rule_Title The Photon operating system must be configured so the x86 Ctrl-Alt-Delete key sequence is disabled on the command line. Vuln_Discuss When the Ctrl-Alt-Del target is enabled, a locally logged-on user who presses Ctrl-Alt-Delete, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of a mixed operating system environment, this can create the risk of short-term loss of systems availability due to unintentional reboot. Check_Content At the command line, run the following command: # systemctl status ctrl-alt-del.target Expected result: ctrl-alt-del.target Loaded: masked (Reason: Unit ctrl-alt-del.target is masked.) Active: inactive (dead) If the "ctrl-alt-del.target" is not "inactive" and "masked", this is a finding. Fix_Text At the command line, run the following command: # systemctl mask ctrl-alt-del.target Not_Reviewed Vuln_Num V-256559 Rule_ID SV-256559r991589_rule Severity medium Rule_Title The Photon operating system must be configured so the "/etc/skel" default scripts are protected from unauthorized modification. Vuln_Discuss If the skeleton files are not protected, unauthorized personnel could change user startup parameters and possibly jeopardize user files. Check_Content At the command line, run the following command: # stat -c "%n permissions are %a and owned by %U:%G" /etc/skel/.[^.]* Expected result: /etc/skel/.bash_logout permissions are 750 and owned by root:root /etc/skel/.bash_profile permissions are 644 and owned by root:root /etc/skel/.bashrc permissions are 750 and owned by root:root If the output does not match the expected result, this is a finding. Fix_Text At the command line, run the following commands: # chmod 750 /etc/skel/.bash_logout # chmod 644 /etc/skel/.bash_profile # chmod 750 /etc/skel/.bashrc # chown root:root /etc/skel/.bash_logout # chown root:root /etc/skel/.bash_profile # chown root:root /etc/skel/.bashrc Not_Reviewed Vuln_Num V-256560 Rule_ID SV-256560r991589_rule Severity medium Rule_Title The Photon operating system must be configured so the "/root" path is protected from unauthorized access. Vuln_Discuss If the "/root" path is accessible to users other than root, unauthorized users could change the root partitions files. Check_Content At the command line, run the following command: # stat -c "%n permissions are %a and owned by %U:%G" /root Expected result: /root permissions are 700 and owned by root:root If the output does not match the expected result, this is a finding. Fix_Text At the command line, run the following commands: # chmod 700 /root # chown root:root /root Not_Reviewed Vuln_Num V-256561 Rule_ID SV-256561r991589_rule Severity medium Rule_Title The Photon operating system must be configured so that all global initialization scripts are protected from unauthorized modification. Vuln_Discuss Local initialization files are used to configure the user's shell environment upon login. Malicious modification of these files could compromise accounts upon login. Check_Content At the command line, run the following command: # find /etc/bash.bashrc /etc/profile /etc/profile.d/ -xdev -type f -a '(' -perm -002 -o -not -user root -o -not -group root ')' -exec ls -ld {} \; If any files are returned, this is a finding. Fix_Text At the command line, run the following commands for each returned file: # chmod o-w <file> # chown root:root <file> Not_Reviewed Vuln_Num V-256562 Rule_ID SV-256562r991589_rule Severity medium Rule_Title The Photon operating system must be configured so that all system startup scripts are protected from unauthorized modification. Vuln_Discuss If system startup scripts are accessible to unauthorized modification, this could compromise the system on startup. Check_Content At the command line, run the following command: # find /etc/rc.d/* -xdev -type f -a '(' -perm -002 -o -not -user root -o -not -group root ')' -exec ls -ld {} \; If any files are returned, this is a finding. Fix_Text At the command line, run the following commands for each returned file: # chmod o-w <file> # chown root:root <file> Not_Reviewed Vuln_Num V-256563 Rule_ID SV-256563r991589_rule Severity medium Rule_Title The Photon operating system must be configured so that all files have a valid owner and group owner. Vuln_Discuss If files do not have valid user and group owners, unintended access to files could occur. Check_Content At the command line, run the following command: # find / -fstype ext4 -nouser -o -nogroup -exec ls -ld {} \; 2>/dev/null If any files are returned, this is a finding. Fix_Text At the command line, run the following command for each returned file: # chown root:root <file> Not_Reviewed Vuln_Num V-256564 Rule_ID SV-256564r991589_rule Severity medium Rule_Title The Photon operating system must be configured so the "/etc/cron.allow" file is protected from unauthorized modification. Vuln_Discuss If cron files and folders are accessible to unauthorized users, malicious jobs may be created. Check_Content At the command line, run the following command: # stat -c "%n permissions are %a and owned by %U:%G" /etc/cron.allow Expected result: /etc/cron.allow permissions are 600 and owned by root:root If the output does not match the expected result, this is a finding. Fix_Text At the command line, run the following commands: # chmod 600 /etc/cron.allow # chown root:root /etc/cron.allow Not_Reviewed Vuln_Num V-256565 Rule_ID SV-256565r991589_rule Severity medium Rule_Title The Photon operating system must be configured so that all cron jobs are protected from unauthorized modification. Vuln_Discuss If cron files and folders are accessible to unauthorized users, malicious jobs may be created. Check_Content At the command line, run the following command: # find /etc/cron.d/ /etc/cron.daily/ /etc/cron.hourly/ /etc/cron.monthly/ /etc/cron.weekly/ -xdev -type f -a '(' -perm -022 -o -not -user root ')' -exec ls -ld {} \; If any files are returned, this is a finding. Fix_Text At the command line, run the following commands for each returned file: # chmod 644 <file> # chown root <file> Not_Reviewed Vuln_Num V-256566 Rule_ID SV-256566r991589_rule Severity medium Rule_Title The Photon operating system must be configured so that all cron paths are protected from unauthorized modification. Vuln_Discuss If cron files and folders are accessible to unauthorized users, malicious jobs may be created. Check_Content At the command line, run the following command: # stat -c "%n permissions are %a and owned by %U:%G" /etc/cron.d /etc/cron.daily /etc/cron.hourly /etc/cron.monthly /etc/cron.weekly Expected result: /etc/cron.d permissions are 755 and owned by root:root /etc/cron.daily permissions are 755 and owned by root:root /etc/cron.hourly permissions are 755 and owned by root:root /etc/cron.monthly permissions are 755 and owned by root:root /etc/cron.weekly permissions are 755 and owned by root:root If the output does not match the expected result, this is a finding. Fix_Text At the command line, run the following commands for each returned file: # chmod 755 <path> # chown root:root <path> Not_Reviewed Vuln_Num V-256567 Rule_ID SV-256567r991589_rule Severity medium Rule_Title The Photon operating system must not forward IPv4 or IPv6 source-routed packets. Vuln_Discuss Source routing is an Internet Protocol mechanism that allows an IP packet to carry information, a list of addresses, that tells a router the path the packet must take. There is also an option to record the hops as the route is traversed. The list of hops taken, the "route record", provides the destination with a return path to the source. This allows the source (the sending host) to specify the route, loosely or strictly, ignoring the routing tables of some or all of the routers. It can allow a user to redirect network traffic for malicious purposes and should therefore be disabled. Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern "net.ipv[4|6].conf.(all|default|eth.*).accept_source_route" Expected result: net.ipv4.conf.all.accept_source_route = 0 net.ipv4.conf.default.accept_source_route = 0 net.ipv4.conf.eth0.accept_source_route = 0 net.ipv6.conf.all.accept_source_route = 0 net.ipv6.conf.default.accept_source_route = 0 net.ipv6.conf.eth0.accept_source_route = 0 If the output does not match the expected result, this is a finding. Note: The number of "ethx" lines returned is dependent on the number of interfaces. Every "ethx" entry must be set to "0". Fix_Text At the command line, run the following command: # for SETTING in $(/sbin/sysctl -aN --pattern "net.ipv[4|6].conf.(all|default|eth.*).accept_source_route"); do sed -i -e "/^${SETTING}/d" /etc/sysctl.conf;echo $SETTING=0>>/etc/sysctl.conf; done # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256568 Rule_ID SV-256568r991589_rule Severity medium Rule_Title The Photon operating system must not respond to IPv4 Internet Control Message Protocol (ICMP) echoes sent to a broadcast address. Vuln_Discuss Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks. Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern ignore_broadcasts Expected result: net.ipv4.icmp_echo_ignore_broadcasts = 1 If the output does not match the expected result, this is a finding. Fix_Text At the command line, run the following commands: # sed -i -e "/^net.ipv4.icmp_echo_ignore_broadcasts/d" /etc/sysctl.conf # echo net.ipv4.icmp_echo_ignore_broadcasts=1>>/etc/sysctl.conf # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256569 Rule_ID SV-256569r991589_rule Severity medium Rule_Title The Photon operating system must prevent IPv4 Internet Control Message Protocol (ICMP) redirect messages from being accepted. Vuln_Discuss ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern "net.ipv4.conf.(all|default|eth.*).accept_redirects" Expected result: net.ipv4.conf.all.accept_redirects = 0 net.ipv4.conf.default.accept_redirects = 0 net.ipv4.conf.eth0.accept_redirects = 0 If the output does not match the expected result, this is a finding. Note: The number of "ethx" lines returned is dependent on the number of interfaces. Every "ethx" entry must be set to "0". Fix_Text At the command line, run the following command: # for SETTING in $(/sbin/sysctl -aN --pattern "net.ipv4.conf.(all|default|eth.*).accept_redirects"); do sed -i -e "/^${SETTING}/d" /etc/sysctl.conf;echo $SETTING=0>>/etc/sysctl.conf; done # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256570 Rule_ID SV-256570r991589_rule Severity medium Rule_Title The Photon operating system must prevent IPv4 Internet Control Message Protocol (ICMP) secure redirect messages from being accepted. Vuln_Discuss ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern "net.ipv4.conf.(all|default|eth.*).secure_redirects" Expected result: net.ipv4.conf.all.secure_redirects = 0 net.ipv4.conf.default.secure_redirects = 0 net.ipv4.conf.eth0.secure_redirects = 0 If the output does not match the expected result, this is a finding. Note: The number of "ethx" lines returned is dependent on the number of interfaces. Every "ethx" entry must be set to "0". Fix_Text At the command line, run the following command: # for SETTING in $(/sbin/sysctl -aN --pattern "net.ipv4.conf.(all|default|eth.*).secure_redirects"); do sed -i -e "/^${SETTING}/d" /etc/sysctl.conf;echo $SETTING=0>>/etc/sysctl.conf; done # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256571 Rule_ID SV-256571r991589_rule Severity medium Rule_Title The Photon operating system must not send IPv4 Internet Control Message Protocol (ICMP) redirects. Vuln_Discuss ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table, possibly revealing portions of the network topology. Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern "net.ipv4.conf.(all|default|eth.*).send_redirects" Expected result: net.ipv4.conf.all.send_redirects = 0 net.ipv4.conf.default.send_redirects = 0 net.ipv4.conf.eth0.send_redirects = 0 If the output does not match the expected result, this is a finding. Note: The number of "ethx" lines returned is dependent on the number of interfaces. Every "ethx" entry must be set to "0". Fix_Text At the command line, run the following command: # for SETTING in $(/sbin/sysctl -aN --pattern "net.ipv4.conf.(all|default|eth.*).send_redirects"); do sed -i -e "/^${SETTING}/d" /etc/sysctl.conf;echo $SETTING=0>>/etc/sysctl.conf; done # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256572 Rule_ID SV-256572r991589_rule Severity medium Rule_Title The Photon operating system must log IPv4 packets with impossible addresses. Vuln_Discuss The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected. Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern "net.ipv4.conf.(all|default|eth.*).log_martians" Expected result: net.ipv4.conf.all.log_martians = 1 net.ipv4.conf.default.log_martians = 1 net.ipv4.conf.eth0.log_martians = 1 If the output does not match the expected result, this is a finding. Note: The number of "ethx" lines returned is dependent on the number of interfaces. Every "ethx" entry must be set to "1". Fix_Text At the command line, run the following command: # for SETTING in $(/sbin/sysctl -aN --pattern "net.ipv4.conf.(all|default|eth.*).log_martians"); do sed -i -e "/^${SETTING}/d" /etc/sysctl.conf;echo $SETTING=1>>/etc/sysctl.conf; done # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256573 Rule_ID SV-256573r991589_rule Severity medium Rule_Title The Photon operating system must use a reverse-path filter for IPv4 network traffic. Vuln_Discuss Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems that are routers for complicated networks but is helpful for end hosts and routers serving small networks. Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern "net.ipv4.conf.(all|default|eth.*)\.rp_filter" Expected result: net.ipv4.conf.all.rp_filter = 1 net.ipv4.conf.default.rp_filter = 1 net.ipv4.conf.eth0.rp_filter = 1 If the output does not match the expected result, this is a finding. Note: The number of "ethx" lines returned is dependent on the number of interfaces. Every "ethx" entry must be set to "1". Fix_Text At the command line, run the following command: # for SETTING in $(/sbin/sysctl -aN --pattern "net.ipv4.conf.(all|default|eth.*)\.rp_filter"); do sed -i -e "/^${SETTING}/d" /etc/sysctl.conf;echo $SETTING=1>>/etc/sysctl.conf; done # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256574 Rule_ID SV-256574r991589_rule Severity medium Rule_Title The Photon operating system must not perform multicast packet forwarding. Vuln_Discuss Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern "net.ipv[4|6].conf.(all|default|eth.*).mc_forwarding" Expected result: net.ipv4.conf.all.mc_forwarding = 0 net.ipv4.conf.default.mc_forwarding = 0 net.ipv4.conf.eth0.mc_forwarding = 0 net.ipv6.conf.all.mc_forwarding = 0 net.ipv6.conf.default.mc_forwarding = 0 net.ipv6.conf.eth0.mc_forwarding = 0 If the output does not match the expected result, this is a finding. Note: The number of "ethx" lines returned is dependent on the number of interfaces. Every "ethx" entry must be set to "0". Fix_Text At the command line, run the following command: # for SETTING in $(/sbin/sysctl -aN --pattern "net.ipv[4|6].conf.(all|default|eth.*).mc_forwarding"); do sed -i -e "/^${SETTING}/d" /etc/sysctl.conf;echo $SETTING=0>>/etc/sysctl.conf; done # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256575 Rule_ID SV-256575r991589_rule Severity medium Rule_Title The Photon operating system must not perform IPv4 packet forwarding. Vuln_Discuss Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this software is used when not required, system network information may be unnecessarily transmitted across the network. Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern "net.ipv4.ip_forward$" Expected result: net.ipv4.ip_forward = 0 If the output does not match the expected result, this is a finding. Fix_Text At the command line, run the following commands: # sed -i -e "/^net.ipv4.ip_forward/d" /etc/sysctl.conf # echo net.ipv4.ip_forward=0>>/etc/sysctl.conf # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256576 Rule_ID SV-256576r991589_rule Severity medium Rule_Title The Photon operating system must send Transmission Control Protocol (TCP) timestamps. Vuln_Discuss TCP timestamps are used to provide protection against wrapped sequence numbers. It is possible to calculate system uptime (and boot time) by analyzing TCP timestamps. These calculated uptimes can help a bad actor in determining likely patch levels for vulnerabilities. Check_Content At the command line, run the following command: # /sbin/sysctl -a --pattern "net.ipv4.tcp_timestamps$" Expected result: net.ipv4.tcp_timestamps = 1 If the output does not match the expected result, this is a finding. Fix_Text At the command line, run the following commands: # sed -i -e "/^net.ipv4.tcp_timestamps/d" /etc/sysctl.conf # echo net.ipv4.tcp_timestamps=1>>/etc/sysctl.conf # /sbin/sysctl --load Not_Reviewed Vuln_Num V-256577 Rule_ID SV-256577r991589_rule Severity medium Rule_Title The Photon operating system must be configured to protect the Secure Shell (SSH) public host key from unauthorized modification. Vuln_Discuss If a public host key file is modified by an unauthorized user, the SSH service may be compromised. Check_Content At the command line, run the following command: # stat -c "%n permissions are %a and owned by %U:%G" /etc/ssh/*key.pub Expected result: /etc/ssh/ssh_host_ecdsa_key.pub permissions are 644 and owned by root:root /etc/ssh/ssh_host_ed25519_key.pub permissions are 644 and owned by root:root /etc/ssh/ssh_host_rsa_key.pub permissions are 644 and owned by root:root If the output does not match the expected result, this is a finding. Fix_Text At the command line, run the following commands for each returned file: # chmod 644 <file> # chown root:root <file> Not_Reviewed Vuln_Num V-256578 Rule_ID SV-256578r991589_rule Severity medium Rule_Title The Photon operating system must be configured to protect the Secure Shell ( SSH) private host key from unauthorized access. Vuln_Discuss If an unauthorized user obtains the private SSH host key file, the host could be impersonated. Check_Content At the command line, run the following command: # stat -c "%n permissions are %a and owned by %U:%G" /etc/ssh/*key Expected result: /etc/ssh/ssh_host_dsa_key permissions are 600 and owned by root:root /etc/ssh/ssh_host_ecdsa_key permissions are 600 and owned by root:root /etc/ssh/ssh_host_ed25519_key permissions are 600 and owned by root:root /etc/ssh/ssh_host_rsa_key permissions are 600 and owned by root:root If any key file listed is not owned by root or not group owned by root or does not have permissions of "0600", this is a finding. Fix_Text At the command line, run the following commands for each returned file: # chmod 600 <file> # chown root:root <file> Not_Reviewed Vuln_Num V-256579 Rule_ID SV-256579r991589_rule Severity medium Rule_Title The Photon operating system must enforce password complexity on the root account. Vuln_Discuss Password complexity rules must apply to all accounts on the system, including root. Without specifying the "enforce_for_root flag", "pam_cracklib" does not apply complexity rules to the root user. While root users can find ways around this requirement, given its superuser power, it is necessary to attempt to force compliance. Check_Content At the command line, run the following command: # grep pam_cracklib /etc/pam.d/system-password|grep --color=always "enforce_for_root" Expected result: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root If the output does not include "enforce_for_root", this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-password Add the following, replacing any existing "pam_cracklib.so" line: password requisite pam_cracklib.so dcredit=-1 ucredit=-1 lcredit=-1 ocredit=-1 minlen=8 minclass=4 difok=4 retry=3 maxsequence=0 enforce_for_root Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256580 Rule_ID SV-256580r991589_rule Severity medium Rule_Title The Photon operating system must protect all boot configuration files from unauthorized modification. Vuln_Discuss Boot configuration files control how the system boots, including single-user mode, auditing, log levels, etc. Improper or malicious configurations can negatively affect system security and availability. Check_Content At the command line, run the following command: # find /boot/*.cfg -xdev -type f -a '(' -perm -002 -o -not -user root -o -not -group root ')' -exec ls -ld {} \; If any files are returned, this is a finding. Fix_Text At the command line, run the following commands for each returned file: # chmod 644 <file> # chown root:root <file> Not_Reviewed Vuln_Num V-256581 Rule_ID SV-256581r991589_rule Severity medium Rule_Title The Photon operating system must protect sshd configuration from unauthorized access. Vuln_Discuss The "sshd_config" file contains all the configuration items for sshd. Incorrect or malicious configuration of sshd can allow unauthorized access to the system, insecure communication, limited forensic trail, etc. Check_Content At the command line, run the following command: # stat -c "%n permissions are %a and owned by %U:%G" /etc/ssh/sshd_config Expected result: /etc/ssh/sshd_config permissions are 600 and owned by root:root If the output does not match the expected result, this is a finding. Fix_Text At the command line, run the following commands: # chmod 600 /etc/ssh/sshd_config # chown root:root /etc/ssh/sshd_config Not_Reviewed Vuln_Num V-256582 Rule_ID SV-256582r991589_rule Severity medium Rule_Title The Photon operating system must protect all "sysctl" configuration files from unauthorized access. Vuln_Discuss The "sysctl" configuration file specifies values for kernel parameters to be set on boot. Incorrect or malicious configuration of these parameters can have a negative effect on system security. Check_Content At the command line, run the following command: # find /etc/sysctl.conf /etc/sysctl.d/* -xdev -type f -a '(' -perm -002 -o -not -user root -o -not -group root ')' -exec ls -ld {} \; If any files are returned, this is a finding. Fix_Text At the command line, run the following commands for each returned file: # chmod 600 <file> # chown root:root <file> Not_Reviewed Vuln_Num V-256583 Rule_ID SV-256583r991590_rule Severity medium Rule_Title The Photon operating system must set the "umask" parameter correctly. Vuln_Discuss The "umask" value influences the permissions assigned to files when they are created. The "umask" setting in "login.defs" controls the permissions for a new user's home directory. By setting the proper "umask", home directories will only allow the new user to read and write files there. Check_Content At the command line, run the following command: # grep ^UMASK /etc/login.defs Example result: UMASK 077 If "UMASK" is not configured to "077", this a finding. Note: "UMASK" should only be specified once in login.defs. Fix_Text Navigate to and open: /etc/login.defs Ensure the "UMASK" line is uncommented and set to the following: UMASK 077 Not_Reviewed Vuln_Num V-256584 Rule_ID SV-256584r991591_rule Severity medium Rule_Title The Photon operating system must configure sshd to disallow HostbasedAuthentication. Vuln_Discuss Secure Shell (SSH) trust relationships enable trivial lateral spread after a host compromise and therefore must be explicitly disabled. Check_Content At the command line, run the following command: # sshd -T|&grep -i HostbasedAuthentication Expected result: hostbasedauthentication no If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "HostbasedAuthentication" line is uncommented and set to the following: HostbasedAuthentication no At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256585 Rule_ID SV-256585r982199_rule Severity medium Rule_Title The Photon operating system must store only encrypted representations of passwords. Vuln_Discuss Passwords must be protected at all times via strong, one-way encryption. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. If they are encrypted with a weak cipher, those passwords are much more vulnerable to offline brute-force attacks. Check_Content At the command line, run the following command: # grep password /etc/pam.d/system-password|grep --color=always "sha512" If the output does not include "sha512", this is a finding. Fix_Text Navigate to and open: /etc/pam.d/system-password Add the argument "sha512" to the "password" line: password required pam_unix.so sha512 shadow try_first_pass Note: On vCenter appliances, the equivalent file must be edited under "/etc/applmgmt/appliance", if one exists, for the changes to persist after a reboot. Not_Reviewed Vuln_Num V-256586 Rule_ID SV-256586r982201_rule Severity medium Rule_Title The Photon operating system must ensure the old passwords are being stored. Vuln_Discuss Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. If the information system or application allows the user to consecutively reuse their password when that password has exceeded its defined lifetime, the result is a password that is not changed per policy requirements. Check_Content At the command line, run the following command: # ls -al /etc/security/opasswd If "/etc/security/opasswd" does not exist, this is a finding. Fix_Text At the command line, run the following commands: # touch /etc/security/opasswd # chown root:root /etc/security/opasswd # chmod 0600 /etc/security/opasswd Not_Reviewed Vuln_Num V-256587 Rule_ID SV-256587r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to restrict AllowTcpForwarding. Vuln_Discuss While enabling Transmission Control Protocol (TCP) tunnels is a valuable function of sshd, this feature is not appropriate for use on single-purpose appliances. Check_Content At the command line, run the following command: # sshd -T|&grep -i AllowTcpForwarding Expected result: allowtcpforwarding no If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "AllowTcpForwarding" line is uncommented and set to the following: AllowTcpForwarding no At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256588 Rule_ID SV-256588r991589_rule Severity medium Rule_Title The Photon operating system must configure sshd to restrict LoginGraceTime. Vuln_Discuss By default, sshd unauthenticated connections are left open for two minutes before being closed. This setting is too permissive as no legitimate login would need such an amount of time to complete a login. Quickly terminating idle or incomplete login attempts will free resources and reduce the exposure any partial logon attempts may create. Check_Content At the command line, run the following command: # sshd -T|&grep -i LoginGraceTime Expected result: logingracetime 30 If the output does not match the expected result, this is a finding. Fix_Text Navigate to and open: /etc/ssh/sshd_config Ensure the "LoginGraceTime" line is uncommented and set to the following: LoginGraceTime 30 At the command line, run the following command: # systemctl restart sshd.service Not_Reviewed Vuln_Num V-256589 Rule_ID SV-256589r959006_rule Severity medium Rule_Title The Photon operating system must implement NIST FIPS-validated cryptography for the following: to provision digital signatures, generate cryptographic hashes, and protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. Vuln_Discuss Use of weak or untested encryption algorithms undermines the purposes of using encryption to protect data. The operating system must implement cryptographic modules adhering to the higher standards approved by the federal government because this provides assurance they have been tested and validated. Check_Content At the command line, run the following command: # cat /proc/sys/crypto/fips_enabled If a value of "1" is not returned, this is a finding. Fix_Text Navigate to and open: /boot/grub2/grub.cfg Locate the kernel command line, which will start with "linux", and add "fips=1" to the end. For example: linux /$photon_linux audit=1 root=$rootpartition $photon_cmdline coredump_filter=0x37 consoleblank=0 $systemd_cmdline fips=1 Reboot the system for the change to take effect. Note: The "fipsify" package must be installed for FIPS mode to work properly. Not_Reviewed Vuln_Num V-256590 Rule_ID SV-256590r991589_rule Severity medium Rule_Title The Photon operating system must disable systemd fallback Domain Name System (DNS). Vuln_Discuss Systemd contains an ability to set fallback DNS servers. This is used for DNS lookups in the event no system-level DNS servers are configured or other DNS servers are specified in the systemd "resolved.conf" file. If uncommented, this configuration contains Google DNS servers by default and could result in DNS leaking information unknowingly in the event DNS is absent or misconfigured at the system level. Check_Content At the command line, run the following command: # resolvectl status | grep 'Fallback DNS' If the output indicates that fallback DNS servers are configured, this is a finding. Fix_Text Navigate to and open: /etc/systemd/resolved.conf Add or update the "FallbackDNS" entry to the following: FallbackDNS= Restart the systemd resolved service by running the following command: # systemctl restart systemd-resolved Note: If this option is not given, a compiled-in list of DNS servers is used instead, which is undesirable. Not_Reviewed