The audit system must be configured to audit all attempts to alter system time through adjtimex.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-38635	RHEL-06-000165	SV-50436r3_rule		Low

Description
Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

STIG	Date
Red Hat Enterprise Linux 6 Security Technical Implementation Guide	2016-12-16

Details

Check Text ( C-46194r2_chk )
To determine if the system is configured to audit calls to the "adjtimex" system call, run the following command: $ sudo grep -w "adjtimex" /etc/audit/audit.rules If the system is configured to audit this activity, it will return a line. If the system is not configured to audit time changes, this is a finding.

Fix Text (F-43584r2_fix)

On a 32-bit system, add the following to "/etc/audit/audit.rules": # audit_time_rules -a always,exit -F arch=b32 -S adjtimex -k audit_time_rules On a 64-bit system, add the following to "/etc/audit/audit.rules": # audit_time_rules -a always,exit -F arch=b64 -S adjtimex -k audit_time_rules The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls: -a always,exit -F arch=b64 -S adjtimex -S settimeofday -S clock_settime -k audit_time_rules