cis-ubuntu1604-v200-4-1-11

name	cis-ubuntu1604-v200-4-1-11
description	Ensure use of privileged commands is collected
category	cis-logging
version	2.0.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-16.04","auditd","logging"]
cis_id	4.1.11
cis_benchmark	CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - Control 4.1.11

Profile

• Level: 2 - Server
• Level: 2 - Workstation
• Assessment Status: Automated

Description

Monitor privileged programs (those that have the setuid and/or setgid bit set on execution) to determine if unprivileged users are running these commands.

Note: Reloading the auditd config to set active settings requires the auditd service to be restarted, and may require a system reboot.

Rationale

Execution of privileged commands by non-privileged users could be an indication of someone trying to gain unauthorized access to the system.

Impact

None.

Audit Procedure

Command Line

Run the following command replacing <partition> with a list of partitions where programs can be executed from on your system:

find <partition> -xdev \( -perm -4000 -o -perm -2000 \) -type f | awk '{print "-a always,exit -F path=" $1 " -F perm=x -F auid>=1000 -F auid!=4294967295 -k privileged" }'

Verify all resulting lines are a .rules file in /etc/audit/rules.d/ and the output of auditctl -l.

Note: The .rules file output will be auid!=-1 not auid!=4294967295.

Expected Result

All privileged commands should have corresponding audit rules.

Remediation

Command Line

To remediate this issue, the system administrator will have to execute a find command to locate all the privileged programs and then add an audit line for each one of them. The audit parameters associated with this are as follows:

• -F path=" $1 " - will populate each file name found through the find command and processed by awk.
• -F perm=x - will write an audit record if the file is executed.
• -F auid>=1000 - will write a record if the user executing the command is not a privileged user.
• -F auid!= 4294967295 - will ignore Daemon events

All audit records should be tagged with the identifier key "privileged".

Run the following command replacing <partition> with a list of partitions where programs can be executed from on your system: