cis-ubuntu2004-v300-6-2-1-2

DevOps & Security

Ensure journald log file access is configured

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_20.04_LTS_Benchmark_v3.0.0/cis-ubuntu2004-v300-6-2-1-2/SKILL.md

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6.2.1.2 Ensure journald log file access is configured (Manual)

Profile

Level 1 - Server
Level 1 - Workstation

Description

Journald will create logfiles that do not already exist on the system. This setting controls what permissions will be applied to these newly created files.

Rationale

It is important to ensure that log files have the correct permissions to ensure that sensitive data is archived and protected.

Audit Procedure

Command Line

Run the following script to verify:

systemd-journald logfiles are mode 0640 or more restrictive
Directories /run/ and /var/lib/systemd/ are mode 0755 or more restrictive
All other configured directories are mode 2755, 0750, or more restrictive

#!/usr/bin/env bash
{
    a_output=() a_output2=()
    l_systemd_config_file="/etc/tmpfiles.d/systemd.conf" l_analyze_cmd="$(readlink -f /bin/systemd-analyze)"
    f_file_chk()
    {
        l_maxperm="$( printf '%o' $(( 0777 & ~$1_perm_mask )) )"
        if [ $(( $l_mode & $l_perm_mask )) -le 0 ] || [[ "$l_type" = "Directory" && "$l_mode" =~ 275{0|5} ]];
    then
            a_out+=(" - $l_type \"$l_logfile\" access is:" \
            "     mode: \"$l_mode\", owned by: \"$l_user\", and group owned by: \"$l_group\"")
        else
            a_out2+=(" - $l_type \"$l_logfile\" access is:" \
            "     mode: \"$l_mode\", owned by: \"$l_user\", and group owned by: \"$l_group\"" \
            "     should be mode: \"$l_maxperm\" or more restrictive")
        fi
    }
    # ... (full audit script from benchmark)
}

Expected Result

Review the output. All files in /var/log/ should have appropriate permissions and ownership.

Remediation

Command Line

If the default configuration is not appropriate for the site specific requirements, copy /usr/lib/tmpfiles.d/systemd.conf to /etc/tmpfiles.d/systemd.conf and modify as required. Recommended mode for logfiles is 0640 or more restrictive.

Default Value

Logfiles are created with mode 0640 by default.

References

NIST SP 800-53 Rev. 5: AC-3, AU-2, AU-12, MP-2, SI-5

CIS Controls

Controls Version	Control	IG 1	IG 2	IG 3
v8	3.3 Configure Data Access Control Lists
v7	14.6 Protect Information through Access Control Lists

MITRE ATT&CK Mappings

Techniques / Sub-techniques	Tactics	Mitigations
T1070, T1070.002, T1083, T1083.000	TA0007	M1022