Successful/unsuccessful uses of the "removexattr" system call in TOSS must generate an audit record.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-253038	TOSS-04-031120	SV-253038r824786_rule		Medium

Description

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). "Removexattr" is a system call that removes extended attributes. 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.

STIG	Date
Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide	2022-08-29

Details

Check Text ( C-56491r824784_chk )

Verify if TOSS is configured to audit the execution of the "removexattr" system call, by running the following command: $ sudo grep -w removexattr /etc/audit/audit.rules -a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b32 -S removexattr -F auid=0 -k perm_mod -a always,exit -F arch=b64 -S removexattr -F auid=0 -k perm_mod If the command does not return all lines, or the lines are commented out, this is a finding.

Fix Text (F-56441r824785_fix)

Configure TOSS to audit the execution of the "removexattr" system call, by adding or updating the following lines to "/etc/audit/rules.d/audit.rules": -a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -k perm_mod -a always,exit -F arch=b32 -S removexattr -F auid=0 -k perm_mod -a always,exit -F arch=b64 -S removexattr -F auid=0 -k perm_mod The audit daemon must be restarted for the changes to take effect.