Cis Ubuntu2004 V300 6 3 3 11

6.3.3.11 Ensure session initiation information is collected (Automated)

Profile

• Level 2 - Server
• Level 2 - Workstation

Description

Monitor session initiation events. The parameters in this section track changes to the files associated with session events.

• /var/run/utmp - tracks all currently logged in users.
• /var/log/wtmp - file tracks logins, logouts, shutdown, and reboot events.
• /var/log/btmp - keeps track of failed login attempts and can be read by entering the command /usr/bin/last -f /var/log/btmp.

All audit records will be tagged with the identifier "session."

Rationale

Monitoring these files for changes could alert a system administrator to logins occurring at unusual hours, which could indicate intruder activity (i.e. a user logging in at a time when they do not normally log in).

Audit Procedure

Command Line

On disk configuration - Run the following command to check the on disk rules:

# awk '/^ *-w/ \
&&(/\/var\/run\/utmp/ \
  ||/\/var\/log\/wtmp/ \
  ||/\/var\/log\/btmp/) \
&&/ +-p *wa/ \
&&(/ key= *[!-~]* *$/||/ -k *[!-~]* *$/)' /etc/audit/rules.d/*.rules

Verify the output matches:

-w /var/run/utmp -p wa -k session
-w /var/log/wtmp -p wa -k session
-w /var/log/btmp -p wa -k session

Running configuration - Run the following command to check loaded rules:

# auditctl -l | awk '/^ *-w/ \
&&(/\/var\/run\/utmp/ \
  ||/\/var\/log\/wtmp/ \
  ||/\/var\/log\/btmp/) \
&&/ +-p *wa/ \
&&(/ key= *[!-~]* *$/||/ -k *[!-~]* *$/)'

Verify the output matches:

-w /var/run/utmp -p wa -k session
-w /var/log/wtmp -p wa -k session
-w /var/log/btmp -p wa -k session

Expected Result

Both on disk and running configuration should show session initiation audit rules.

Remediation

Command Line

Edit or create a file in the /etc/audit/rules.d/ directory, ending in .rules extension, with the relevant rules to monitor session initiation information.

Example:

# printf "
-w /var/run/utmp -p wa -k session
-w /var/log/wtmp -p wa -k session
-w /var/log/btmp -p wa -k session
" >> /etc/audit/rules.d/50-session.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

References

1. NIST SP 800-53 Rev. 5: AU-3
2. STIG ID: UBTU-20-010279 | RULE ID: SV-238317r991581 | CAT II
3. STIG ID: UBTU-20-010278 | RULE ID: SV-238316r991581 | CAT II
4. STIG ID: UBTU-20-010277 | RULE ID: SV-238315r991581 | CAT II
5. STIG ID: UBTU-22-654195 | RULE ID: SV-260641r991581 | CAT II
6. STIG ID: UBTU-22-654200 | RULE ID: SV-260642r991581 | CAT II
7. STIG ID: UBTU-22-654205 | RULE ID: SV-260643r991581 | CAT II

CIS Controls

MITRE ATT&CK Mappings: T1562, T1562.006 / TA0001 / M1047