cis-ubuntu1204-v110-8-1-4

name	cis-ubuntu1204-v110-8-1-4
description	Record Events That Modify Date and Time Information
category	cis-os-hardening
version	1.1.0
author	cyberstrike-official
tags	["cis","ubuntu",12.04,"linux","logging","auditd","time","date"]
cis_id	8.1.4
cis_benchmark	CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

8.1.4 Record Events That Modify Date and Time Information (Scored)

Profile Applicability

• Level 2

Description

Capture events where the system date and/or time has been modified. The parameters in this section are set to determine if the adjtimex (tune kernel clock), settimeofday (Set time, using timeval and timezone structures), stime (using seconds since 1/1/1970) or clock_settime (allows for the setting of several internal clocks and timers) system calls have been executed and always write an audit record to the /var/log/audit.log file upon exit, tagging the records with the identifier "time-change".

Rationale

Unexpected changes in system date and/or time could be a sign of malicious activity on the system.

Audit Procedure

Using Command Line

On a 64 bit system, perform the following command and ensure the output is as shown:

grep time-change /etc/audit/audit.rules

On a 32 bit system, perform the following command and ensure the output is as shown:

grep time-change /etc/audit/audit.rules

Expected Result

For 64 bit systems:

-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k time-change
-a always,exit -F arch=b32 -S adjtimex -S settimeofday -S stime -k time-change
-a always,exit -F arch=b64 -S clock_settime -k time-change
-a always,exit -F arch=b32 -S clock_settime -k time-change
-w /etc/localtime -p wa -k time-change

For 32 bit systems:

-a always,exit -F arch=b32 -S adjtimex -S settimeofday -S stime -k time-change
-a always,exit -F arch=b32 -S clock_settime -k time-change
-w /etc/localtime -p wa -k time-change

Remediation

Using Command Line

For 64 bit systems, add the following lines to the /etc/audit/audit.rules file:

-a always,exit -F arch=b64 -S adjtimex -S settimeofday -k time-change
-a always,exit -F arch=b32 -S adjtimex -S settimeofday -S stime -k time-change
-a always,exit -F arch=b64 -S clock_settime -k time-change
-a always,exit -F arch=b32 -S clock_settime -k time-change
-w /etc/localtime -p wa -k time-change

pkill -P 1-HUP auditd