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CIS Ubuntu 14.04 LTS - 6.1.11 Ensure no unowned files or directories exist

DevOps & Security
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Find and remediate files and directories without a valid owner

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How to use this skill

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Prompt to paste
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_14.04_LTS_Benchmark_v2.1.0/cis-ubuntu1404-v210-6-1-11/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-ubuntu-14-04-lts-6-1-11-ensure-no-unowned-files-or-directories-exist/. Do not write files or run scripts until I approve.

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6.1.11 Ensure no unowned files or directories exist (Scored)

Profile Applicability

  • Level 1 - Server
  • Level 1 - Workstation

Description

Sometimes when administrators delete users from the password file they neglect to remove all files owned by those users from the system.

Rationale

A new user who is assigned the deleted user's user ID or group ID may then end up "owning" these files, and thus have more access on the system than was intended.

Audit Procedure

Run the following command and verify no files are returned:

df --local -P | awk {'if (NR!=1) print $6'} | xargs -I '{}' find '{}' -xdev -nouser

The command above only searches local filesystems, there may still be compromised items on network mounted partitions. Additionally the --local option to df is not universal to all versions, it can be omitted to search all filesystems on a system including network mounted filesystems or the following command can be run manually for each partition:

find <partition> -xdev -nouser

Expected Result

No output should be returned.

Remediation

Locate files that are owned by users or groups not listed in the system configuration files, and reset the ownership of these files to some active user on the system as appropriate.

Default Value

Not applicable.

References

None

CIS Controls

14 Controlled Access Based on the Need to Know - Controlled Access Based on the Need to Know

Profile

  • Level 1