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V-275620

CAT I (High)

Ubuntu OS must not allow unattended or automatic login via SSH.

Rule ID

SV-275620r1147910_rule

STIG

Riverbed NetIM OS Security Technical Implementation Guide

Version

V1R1

CCIs

CCI-000366

Discussion

Failure to restrict system access to authenticated users negatively impacts Ubuntu OS security.

Check Content

Verify unattended or automatic login via SSH is disabled by using the following command: 
 
     $ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iEH '(permit(.*?)(passwords|environment))' 
     /etc/ssh/sshd_config:PermitEmptyPasswords no 
     /etc/ssh/sshd_config:PermitUserEnvironment no 
 
If "PermitEmptyPasswords" and "PermitUserEnvironment" are not set to "no", are commented out, are missing, or conflicting results are returned, this is a finding.

Fix Text

Configure the SSH server to not allow unattended or automatic login to the system.  
  
Add or modify the following lines in the "/etc/ssh/sshd_config" file:  
  
PermitEmptyPasswords no 
PermitUserEnvironment no 
  
Restart the SSH daemon for the changes to take effect: 
  
     $ sudo systemctl restart sshd.service