Cis Ubuntu1804 V220 5 2 4 11

5.2.4.11 Ensure cryptographic mechanisms are used to protect the integrity of audit tools

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 the integrity of the tools used for auditing purposes is a critical step toward ensuring the integrity of audit information. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity.

Attackers may replace the audit tools or inject code into the existing tools with the purpose of providing the capability to hide or erase system activity from the audit logs.

Audit tools should be cryptographically signed in order to provide the capability to identify when the audit tools have been modified, manipulated, or replaced. An example is a checksum hash of the file or files.

Audit

Verify that Advanced Intrusion Detection Environment (AIDE) is properly configured. Run the following command to verify that AIDE is configured to use cryptographic mechanisms to protect the integrity of audit tools:

grep -Ps -- '(\/sbin\/(audit|au)\H*\b)' /etc/aide/aide.conf /etc/aide.conf.d/*.conf /etc/aide/aide.conf.d/*.conf

Verify the output includes:

/sbin/auditctl p+i+n+u+g+s+b+acl+xattrs+sha512
/sbin/auditd p+i+n+u+g+s+b+acl+xattrs+sha512
/sbin/ausearch p+i+n+u+g+s+b+acl+xattrs+sha512
/sbin/aureport p+i+n+u+g+s+b+acl+xattrs+sha512
/sbin/autrace p+i+n+u+g+s+b+acl+xattrs+sha512
/sbin/augenrules p+i+n+u+g+s+b+acl+xattrs+sha512

Remediation

Add or edit the following lines to /etc/aide/aide.conf or a /etc/aide/aide.conf.d/ configuration file:

/sbin/auditctl p+i+n+u+g+s+b+acl+xattrs+sha512
/sbin/auditd p+i+n+u+g+s+b+acl+xattrs+sha512
/sbin/ausearch p+i+n+u+g+s+b+acl+xattrs+sha512
/sbin/aureport p+i+n+u+g+s+b+acl+xattrs+sha512
/sbin/autrace p+i+n+u+g+s+b+acl+xattrs+sha512
/sbin/augenrules p+i+n+u+g+s+b+acl+xattrs+sha512

References

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

Metadata

• Profile Applicability: Level 1 - Server, Level 1 - Workstation
• Category: cis-logging
• Tags: cis, ubuntu, linux, ubuntu-18.04, auditing, auditd
• Version: 2.2.0
• Severity Boost: {}
• Automated: Yes
• CIS Controls:
  • v8: 3.3 Configure Data Access Control Lists
  • v7: 14.6 Protect Information through Access Control Lists
• MITRE ATT&CK:
  • Tactics: TA0007 (Discovery)
  • Techniques: T1070, T1070.002, T1083, T1083.000
  • Mitigations: M1047 (Audit)