Vulnerability Discussion

The actions taken by system administrators must be audited to keep a record of what was executed on the system, as well as for accountability purposes. Editing the sudoers file may be sign of an attacker trying to establish persistent methods to a system, auditing the editing of the sudoers files mitigates this risk.

Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221

Check

Verify Amazon Linux 2023 generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/sudoers.d/" with the following command:

$ sudo auditctl -l | grep /etc/sudoers.d
-w /etc/sudoers.d/ -p wa -k identity

If the command does not return a line, or the line is commented out, this is a finding.

Fix

Configure Amazon Linux 2023 to generate audit records for all account creations, modifications, disabling, and termination events that affect "/etc/sudoers.d/".

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

-w /etc/sudoers.d/ -p wa -k identity

To load the rules to the kernel immediately, use the following command:

$ sudo augenrules --load