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cis-ubuntu1804-v220-1-1-9

DevOps & Security
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Disable Automounting

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How to use this skill

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I want to install this Agent Skill for this project in Codex.

Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_18.04_LTS_Benchmark_v2.2.0/cis-ubuntu1804-v220-1-1-9/SKILL.md

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First, summarize what it does, its dependencies, license status if identifiable, and any risks. Show the exact files you propose to add under .agents/skills/cis-ubuntu1804-v220-1-1-9/. Do not write files or run scripts until I approve.

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Copying this prompt does not install or run the skill. Review third-party files before use. Codex skill guide

Disable Automounting

Profile

Level 1 - Server / Level 2 - Workstation, Assessment: Automated

Description

autofs allows automatic mounting of devices, typically including CD/DVDs and USB drives.

Rationale

With automounting enabled anyone with physical access could attach a USB drive or disc and have its contents available in system even if they lacked permissions to mount it themselves. autofs can be configured to mount on insertion or accessed directly.

Impact

The use of portable hard drives is very common for workstation users. If your organization allows the use of portable storage or media on workstations and physical access controls to workstations are considered adequate, the risk of autofs can be mitigated.

Audit Procedure

Command Line

Run the following commands to verify autofs is not installed or the autofs service is masked:

If autofs is not installed:

# dpkg-query -W -f='${binary:Package}\t${Status}\t${db:Status-Status}\n' autofs

If autofs is installed, verify the service is masked:

# systemctl is-enabled autofs 2>/dev/null | grep 'enabled'

Expected Result

If autofs is not installed, dpkg-query should return:

dpkg-query: no packages found matching autofs

If autofs is installed, systemctl is-enabled autofs should NOT return enabled. Ideally the service should be masked.

Remediation

Command Line

Run one of the following commands:

To remove autofs:

apt purge autofs

-OR-

To disable and mask the autofs service:

systemctl stop autofs
systemctl mask autofs

Default Value

autofs is not installed by default on Ubuntu 18.04.

References

  1. NIST SP 800-53 Rev. 5: SI-3, MP-7

CIS Controls

v8 - 10.3 Disable Autorun and Autoplay for Removable Media (IG 1, IG 2, IG 3) v7 - 8.5 Configure Devices Not To Auto-run Content (IG 1, IG 2, IG 3)

MITRE ATT&CK Mappings: T1068, T1068.000, T1203, T1203.000, T1211, T1211.000, T1212, T1212.000 (TA0001, TA0008) - M1042