The Ubuntu operating system must permit only authorized groups ownership of the audit log files.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-238247	UBTU-20-010124	SV-238247r653916_rule		Medium

Description
Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality. Audit information includes all information (e.g., audit records, audit settings, audit reports) needed to successfully audit operating system activity. Satisfies: SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029

STIG	Date
Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide	2021-03-23

Details

Check Text ( C-41457r653914_chk )
Verify the group owner is set to own newly created audit logs in the audit configuration file with the following command: $ sudo grep -iw log_group /etc/audit/auditd.conf log_group = adm If the value of the "log_group" parameter is other than "root" or "adm", this is a finding. 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, determine if the audit log files are owned by the "root" or "adm" group by using the following command: $ sudo stat -c "%n %G" /var/log/audit/* /var/log/audit/audit.log root If the audit log files are owned by a group other than "root" or "adm", this is a finding.

Check Text ( C-41457r653914_chk )

Verify the group owner is set to own newly created audit logs in the audit configuration file with the following command:

$ sudo grep -iw log_group /etc/audit/auditd.conf
log_group = adm

If the value of the "log_group" parameter is other than "root" or "adm", this is a finding.

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, determine if the audit log files are owned by the "root" or "adm" group by using the following command:

$ sudo stat -c "%n %G" /var/log/audit/*
/var/log/audit/audit.log root

If the audit log files are owned by a group other than "root" or "adm", this is a finding.

Fix Text (F-41416r653915_fix)
Configure the audit log directory and its underlying files to be owned by "adm" group. 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 files to be owned by "adm" group by using the following command: $ sudo chown :adm /var/log/audit/ Set the "log_group" parameter of the audit configuration file to the "adm" value so that when a new log file is created, its group owner is properly set: $ sed -i '/^log_group/D' /etc/audit/auditd.conf $ sed -i /^log_file/a'log_group = adm' /etc/audit/auditd.conf Last, signal the audit daemon to reload the configuration file: $ sudo systemctl kill auditd -s SIGHUP"

Fix Text (F-41416r653915_fix)

Configure the audit log directory and its underlying files to be owned by "adm" group.

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 files to be owned by "adm" group by using the following command:

$ sudo chown :adm /var/log/audit/

Set the "log_group" parameter of the audit configuration file to the "adm" value so that when a new log file is created, its group owner is properly set:

$ sed -i '/^log_group/D' /etc/audit/auditd.conf
$ sed -i /^log_file/a'log_group = adm' /etc/audit/auditd.conf

Last, signal the audit daemon to reload the configuration file:

$ sudo systemctl kill auditd -s SIGHUP"