STIGQter: STIG Summary: Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide Version: 1 Release: 1 Benchmark Date: 10 Mar 2021:

The Ubuntu operating system must be configured so that the script which runs each 30 days or less to check file integrity is the default one.

DISA Rule

SV-238236r653883_rule

Vulnerability Number

V-238236

Group Title

SRG-OS-000446-GPOS-00200

Rule Version

UBTU-20-010074

Severity

CAT II

CCI(s)

• CCI-002699 - The information system performs verification of the correct operation of organization-defined security functions: when the system is in an organization-defined transitional state; upon command by a user with appropriate privileges; and/or on an organization-defined frequency.

Weight

10

Fix Recommendation

The cron file for AIDE is fairly complex as it creates the report. This file is installed with the "aide-common" package, and the default can be restored by copying it from the package:

Download the original package to the /tmp dir:

$ cd /tmp; apt download aide-common

Extract the aide script to its original place:

$ dpkg-deb --fsys-tarfile /tmp/aide-common_*.deb | sudo tar -x ./usr/share/aide/config/cron.daily/aide -C /

Copy it to the cron.daily directory:

$ sudo cp -f /usr/share/aide/config/cron.daily/aide /etc/cron.daily/aide

Check Contents

Verify that the Advanced Intrusion Detection Environment (AIDE) default script used to check file integrity each 30 days or less is unchanged.

Download the original aide-common package in the /tmp directory:

$ cd /tmp; apt download aide-common

Fetch the SHA1 of the original script file:

$ dpkg-deb --fsys-tarfile /tmp/aide-common_*.deb | tar -xO ./usr/share/aide/config/cron.daily/aide | sha1sum
32958374f18871e3f7dda27a58d721f471843e26 -

Compare with the SHA1 of the file in the daily or monthly cron directory:

$ sha1sum /etc/cron.{daily,monthly}/aide 2>/dev/null
32958374f18871e3f7dda27a58d721f471843e26 /etc/cron.daily/aide

If there is no AIDE script file in the cron directories, or the SHA1 value of at least one file in the daily or monthly cron directory does not match the SHA1 of the original, this is a finding.

Vulnerability Number

V-238236

Documentable

False

Rule Version

UBTU-20-010074

Severity Override Guidance

Verify that the Advanced Intrusion Detection Environment (AIDE) default script used to check file integrity each 30 days or less is unchanged.

Download the original aide-common package in the /tmp directory:

$ cd /tmp; apt download aide-common

Fetch the SHA1 of the original script file:

$ dpkg-deb --fsys-tarfile /tmp/aide-common_*.deb | tar -xO ./usr/share/aide/config/cron.daily/aide | sha1sum
32958374f18871e3f7dda27a58d721f471843e26 -

Compare with the SHA1 of the file in the daily or monthly cron directory:

$ sha1sum /etc/cron.{daily,monthly}/aide 2>/dev/null
32958374f18871e3f7dda27a58d721f471843e26 /etc/cron.daily/aide

If there is no AIDE script file in the cron directories, or the SHA1 value of at least one file in the daily or monthly cron directory does not match the SHA1 of the original, this is a finding.

Check Content Reference

M

Target Key

5318

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