The Ubuntu operating system must be configured so that the audit log directory is not write-accessible by unauthorized users.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-100689	UBTU-18-010308	SV-109793r1_rule		Medium

Description
If audit information were to become compromised, then forensic analysis and discovery of the true source of potentially malicious system activity is impossible to achieve. To ensure the veracity of audit information, the operating system must protect audit information from unauthorized deletion. This requirement can be achieved through multiple methods, which will depend upon system architecture and design. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit information system activity.

Description

If audit information were to become compromised, then forensic analysis and discovery of the true source of potentially malicious system activity is impossible to achieve. To ensure the veracity of audit information, the operating system must protect audit information from unauthorized deletion. This requirement can be achieved through multiple methods, which will depend upon system architecture and design. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit information system activity.

STIG	Date
Canonical Ubuntu 18.04 LTS Security Technical Implementation Guide	2020-05-29

Details

Check Text ( C-99551r2_chk )
Verify that the audit log directory has a mode of "0750" or less permissive. First determine where the audit logs are stored with the following command: # sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Using the path of the directory containing the audit logs, check if the directory has a mode of "0750" or less by using the following command: # sudo stat -c "%n %a" /var/log/audit /var/log/audit 750 If the audit log directory has a mode more permissive than "0750", this is a finding.

Check Text ( C-99551r2_chk )

Verify that the audit log directory has a mode of "0750" or less permissive.

First determine where the audit logs are stored with the following command:

# sudo grep -iw log_file /etc/audit/auditd.conf
log_file = /var/log/audit/audit.log

Using the path of the directory containing the audit logs, check if the directory has a mode of "0750" or less by using the following command:

# sudo stat -c "%n %a" /var/log/audit
/var/log/audit 750

If the audit log directory has a mode more permissive than "0750", this is a finding.

Fix Text (F-106375r1_fix)
Configure the audit log directory to have a mode of "0750" or less permissive. First determine where the audit logs are stored with the following command: # sudo grep -iw log_file /etc/audit/auditd.conf log_file = /var/log/audit/audit.log Using the path of the directory containing the audit logs, configure the audit log directory to have a mode of "0750" or less permissive by using the following command: # chmod -R g-w,o-rwx /var/log/audit

Fix Text (F-106375r1_fix)

Configure the audit log directory to have a mode of "0750" or less permissive.

First determine where the audit logs are stored with the following command:

# sudo grep -iw log_file /etc/audit/auditd.conf
log_file = /var/log/audit/audit.log

Using the path of the directory containing the audit logs, configure the audit log directory to have a mode of "0750" or less permissive by using the following command:

# chmod -R g-w,o-rwx /var/log/audit