Vulnerability Discussion

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-000326-GPOS-00126, SRG-OS-000327-GPOS-00127, SRG-OS-000755-GPOS-00220

Check

Verify that OL 9 is configured to audit the execution of the execve system call with the following command:

$ sudo auditctl -l | grep execve
-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k execpriv
-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k execpriv
-a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k execpriv
-a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k execpriv

If the command does not return all lines or the lines are commented out, this is a finding.

Fix

Configure OL 9 to audit the execution of the execve system call.

Add or update the following file system rules to "/etc/audit/rules.d/audit.rules":

-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k execpriv
-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k execpriv
-a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k execpriv
-a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k execpriv

The audit daemon must be restarted for the changes to take effect.

Restart auditd:
$ sudo service auditd restart

Note: Users must reboot to view above results with command "auditctl -l | grep execve".