Title

The Ubuntu operating system must use cryptographic mechanisms to protect the integrity of audit tools. (Cat II impact)

Discussion

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. 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. It is not uncommon for attackers to 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. To address this risk, audit tools must 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.

Check Content

Verify that Advanced Intrusion Detection Environment (AIDE) to properly configured to use cryptographic mechanisms to protect the integrity of audit tools. Check the selection lines that aide is configured to add/check with the following command: # egrep '(\/usr\/sbin\/(audit|au))' /etc/aide/aide.conf /usr/sbin/auditctl p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/auditd p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/ausearch p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/aureport p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/autrace p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/audispd p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/augenrules p+i+n+u+g+s+b+acl+xattr+sha512 If any of the seven audit tools does not have an appropriate selection line, this is a finding.

Fix Text

Add or update the following selection lines to "/etc/aide/aide.conf", in order to protect the integrity of the audit tools. # Audit Tools /usr/sbin/auditctl p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/auditd p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/ausearch p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/aureport p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/autrace p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/audispd p+i+n+u+g+s+b+acl+xattr+sha512 /usr/sbin/augenrules p+i+n+u+g+s+b+acl+xattr+sha512

Additional Identifiers

Rule ID: SV-214987r610931_rule

Vulnerability ID: V-214987

Group Title: SRG-OS-000278-GPOS-00108

Expert Comments

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