Rule ID
SV-240500r852561_rule
Version
V2R2
CCIs
Once an attacker establishes initial 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 simply enable a new or disabled account. Notification of account enabling is one method for mitigating this risk. A comprehensive account management process will ensure an audit trail, which documents the creation of operating system user accounts and notifies System Administrators and Information System Security Officers (ISSO) that it exists. Such a process greatly reduces the risk that accounts will be surreptitiously enabled and provides logging that can be used for forensic purposes. In order to detect and respond to events that affect user accessibility and application processing, operating systems must audit account enabling actions and, as required, notify the appropriate individuals so they can investigate the event. To address access requirements, many operating systems can be integrated with enterprise-level authentication/access/auditing mechanisms that meet or exceed access control policy requirements.
Determine if execution of the "usermod" and "groupmod" executable are audited: # auditctl -l | egrep '(usermod|groupmod)' If either "usermod" or "groupmod" are not listed with a permissions filter of at least "x", this is a finding. Determine if execution of the "userdel" and "groupdel" executable are audited: # auditctl -l | egrep '(userdel|groupdel)' If either "userdel" or "groupdel" are not listed with a permissions filter of at least "x", this is a finding. Determine if execution of "useradd" and "groupadd" are audited: # auditctl -l | egrep '(useradd|groupadd)' If either "useradd" or "groupadd" are not listed with a permissions filter of at least "x", this is a finding. Determine if execution of the "passwd" executable is audited: # auditctl -l | grep “/usr/bin/passwd” If "/usr/bin/passwd" is not listed with a permissions filter of at least "x", this is a finding. Determine if /etc/passwd, /etc/shadow, /etc/group, and /etc/security/opasswd are audited for writing: # auditctl -l | egrep '(/etc/passwd|/etc/shadow|/etc/group|/etc/security/opasswd)' If any of these are not listed with a permissions filter of at least "w", this is a finding.
Configure "execute" auditing of the "usermod" and "groupmod" executables. Add the following to the /etc/audit/audit.rules file: -w /usr/sbin/usermod -p x -k usermod -w /usr/sbin/groupmod -p x -k groupmod Configure "execute" auditing of the "userdel" and "groupdel" executables. Add the following to the /etc/audit/audit.rules file: -w /usr/sbin/userdel -p x -k userdel -w /usr/sbin/groupdel -p x -k groupdel Configure "execute" auditing of the "useradd" and "groupadd" executables. Add the following to audit.rules: -w /usr/sbin/useradd -p x -k useradd -w /usr/sbin/groupadd -p x -k groupadd Configure "execute" auditing of the "passwd" executable. Add the following to the aud.rules: -w /usr/bin/passwd -p x -k passwd Configure "write" auditing of the "passwd", "shadow", "group", and "opasswd" files. Add the following to the /etc/audit/audit.rules file: -w /etc/passwd -p wa -k passwd -w /etc/shadow -p wa -k shadow -w /etc/group -p wa -k group -w /etc/security/opasswd -p wa -k opasswd Restart the auditd service: # service auditd restart