cis-ubuntu1804-v220-5-2-3-12

name	cis-ubuntu1804-v220-5-2-3-12
description	Ensure login and logout events are collected
version	2.2.0
category	cis-logging
tags	["cis","ubuntu","linux","ubuntu-18.04","auditing","auditd"]
author	CIS Benchmarks
target	{"platform":"linux","version":"18.04"}
severity_boost	{}

CIS Ubuntu 18.04 - Ensure login and logout events are collected (5.2.3.12)

Metadata

• ID: cis-ubuntu1804-v220-5-2-3-12
• Title: Ensure login and logout events are collected
• CIS Control: 5.2.3.12
• Profile Applicability: Level 2 - Server, Level 2 - Workstation
• Benchmark: CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0
• Category: cis-logging
• Tags: cis, ubuntu, linux, ubuntu-18.04, auditing, auditd
• Severity: medium
• Version: 2.2.0

Description

Monitor login and logout events. The parameters below track changes to files associated with login/logout events.

• /var/log/lastlog - maintain records of the last time a user successfully logged in
• /var/run/faillock - directory maintains records of login failures via the pam_faillock module

Rationale

Monitoring login/logout events could provide a system administrator with information associated with brute force attacks against user logins.

Impact

None

Audit

On Disk Configuration (64-bit)

UID_MIN=$(awk '/^\s*UID_MIN/{print $2}' /etc/login.defs)
[ -n "${UID_MIN}" ] && awk "/^ *-a *always,exit/ \
&&/ -F *logins/ \
&&/ -k *logins/" /etc/audit/rules.d/*.rules \
|| printf "ERROR: Variable 'UID_MIN' is unset.\n"

Expected Output:

-w /var/log/lastlog -p wa -k logins
-w /var/run/faillock -p wa -k logins

Running Configuration (64-bit)

UID_MIN=$(awk '/^\s*UID_MIN/{print $2}' /etc/login.defs)
[ -n "${UID_MIN}" ] && auditctl -l | awk "/^ *-a *always,exit/ \
&&/ -F *logins/ \
&&/ -k *logins/"

Expected Output:

-w /var/log/lastlog -p wa -k logins
-w /var/run/faillock -p wa -k logins

32-bit Systems

Follow the same procedures as for 64 bit systems and ignore any entries with b64.

Remediation

Create Audit Rules

Edit or create a file in the /etc/audit/rules.d/ directory, ending in .rules extension, with the relevant rules to monitor login and logout events.

Example:

printf "
-w /var/log/lastlog -p wa -k logins
-w /var/run/faillock -p wa -k logins
" >> /etc/audit/rules.d/50-login.rules

Load Audit Rules

Merge and load the rules into active configuration:

augenrules --load

Check if reboot is required:

if [[ $(auditctl -s | grep "enabled") =~ "2" ]]; then printf "Reboot required to load rules\n"; fi

32-bit Systems

Follow the same procedures as for 64 bit systems and ignore any entries with b64.

References

• NIST SP 800-53 Rev. 5: AU-3

CIS Controls

• v8: 8.5 Collect Detailed Audit Logs
• v7: 4.9 Log and Alert on Unsuccessful Administrative Account Login, 16.13 Alert on Account Login Behavior Deviation

MITRE ATT&CK Mappings

• Techniques: T1562, T1562.006
• Tactics: TA0001
• Mitigations: M1047

Additional Information

Potential Reboot Required

If the auditing configuration is locked (-e 2), then augenrules will not warn in any way that rules could not be loaded into the running configuration. A system reboot will be required to load the rules into the running configuration.

System Call Structure

For performance (man 7 audit.rules) reasons it is preferable to have all the system calls on one line. However, your configuration may have them on one line each or some other combination. This is important to understand for both the auditing and remediation sections as the examples given are optimized for performance as per the man page.