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Successful/unsuccessful uses of the unix_update in RHEL 8 must generate an audit record.


Overview

Finding ID Version Rule ID IA Controls Severity
V-230426 RHEL-08-030310 SV-230426r627750_rule Medium
Description
Reconstruction of harmful events or forensic analysis is not possible if audit records do not contain enough information. At a minimum, the organization must audit the full-text recording of privileged commands. The organization must maintain audit trails in sufficient detail to reconstruct events to determine the cause and impact of compromise. "Unix_update" is a helper program for the "pam_unix" module that updates the password for a given user. It is not intended to be run directly from the command line and logs a security violation if done so. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
STIG Date
Red Hat Enterprise Linux 8 Security Technical Implementation Guide 2021-03-04

Details

Check Text ( C-33095r568024_chk )
Verify that an audit event is generated for any successful/unsuccessful use of the "unix_update" by performing the following command to check the file system rules in "/etc/audit/audit.rules":

$ sudo grep -w "unix_update" /etc/audit/audit.rules

-a always,exit -F path=/usr/sbin/unix_update -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update

If the command does not return a line, or the line is commented out, this is a finding.
Fix Text (F-33070r568025_fix)
Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "unix_update" by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file:

-a always,exit -F path=/usr/sbin/unix_update -F perm=x -F auid>=1000 -F auid!=unset -k privileged-unix-update

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