Cis Ubuntu2004 V300 6 3 4 8

6.3.4.8 Ensure audit tools mode is configured (Automated)

Profile Applicability

• Level 2 - Server
• Level 2 - Workstation

Description

Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators.

Rationale

Protecting audit information includes identifying and protecting the tools used to view and manipulate log data. Protecting audit tools is necessary to prevent unauthorized operation on audit information.

Audit

Run the following script to verify the audit tools are mode 0755 or more restrictive:

#!/usr/bin/env bash
{
  l_output="" l_output2="" l_perm_mask="0022"
  l_maxperm="$( printf '%o' $(( 0777 & ~$l_perm_mask )) )"
  a_audit_tools=("/sbin/auditctl" "/sbin/aureport" "/sbin/ausearch" "/sbin/autrace" "/sbin/auditd" "/sbin/augenrules")
  for l_audit_tool in "${a_audit_tools[@]}"; do
    l_mode="$(stat -Lc '%#a' "$l_audit_tool")"
    if [ $(( $l_mode & $l_perm_mask )) -gt 0 ]; then
      l_output2="$l_output2\n - Audit tool \"$l_audit_tool\" is mode: \"$l_mode\" and should be mode: \"$l_maxperm\" or more restrictive"
    else
      l_output="$l_output\n - Audit tool \"$l_audit_tool\" is correctly configured to mode: \"$l_mode\""
    fi
  done
  if [ -z "$l_output2" ]; then
    echo -e "\n- Audit Result:\n ** PASS **\n - * Correctly configured * :$l_output"
  else
    echo -e "\n- Audit Result:\n ** FAIL **\n - * Reasons for audit failure * :$l_output2\n"
    [ -n "$l_output" ] && echo -e "\n - * Correctly configured * :\n$l_output\n"
  fi
  unset a_audit_tools
}

Remediation

Run the following command to remove more permissive mode from the audit tools:

chmod go-w /sbin/auditctl /sbin/aureport /sbin/ausearch /sbin/autrace /sbin/auditd /sbin/augenrules

References

1. NIST SP 800-53 Rev. 5: AU-3

CIS Controls

• v8: 3.3 Configure Data Access Control Lists
• v7: 14.6 Protect Information through Access Control Lists

MITRE ATT&CK Mappings

• Techniques: T1070, T1070.002, T1083, T1083.000
• Tactics: TA0007
• Mitigations: M1022