CIS Ubuntu 14.04 LTS - 6.2.8 Ensure users' home directories permissions are 750 or more restrictive

DevOps & Security

Verify user home directories have permissions of 750 or more restrictive

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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-v210-6-2-8/SKILL.md

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6.2.8 Ensure users' home directories permissions are 750 or more restrictive (Scored)

Profile Applicability

Level 1 - Server
Level 1 - Workstation

Description

While the system administrator can establish secure permissions for users' home directories, the users can easily override these.

Rationale

Group or world-writable user home directories may enable malicious users to steal or modify other users' data or to gain another user's system privileges.

Audit Procedure

Run the following script and verify no results are returned:

#!/bin/bash

cat /etc/passwd | egrep -v '^(root|halt|sync|shutdown)' | awk -F: '($7 != "/usr/sbin/nologin" && $7 != "/bin/false") { print $1 " " $6 }' | while read user dir; do
  if [ ! -d "$dir" ]; then
     echo "The home directory ($dir) of user $user does not exist."
  else
     dirperm=`ls -ld $dir | cut -f1 -d" "`
     if [ `echo $dirperm | cut -c6 ` != "-" ]; then
        echo "Group Write permission set on the home directory ($dir) of user $user"
     fi
     if [ `echo $dirperm | cut -c8` != "-" ]; then
        echo "Other Read permission set on the home directory ($dir) of user $user"
     fi
     if [ `echo $dirperm | cut -c9` != "-" ]; then
        echo "Other Write permission set on the home directory ($dir) of user $user"
     fi
     if [ `echo $dirperm | cut -c10` != "-" ]; then
        echo "Other Execute permission set on the home directory ($dir) of user $user"
     fi
  fi
done

Expected Result

No output should be returned.

Remediation

Making global modifications to user home directories without alerting the user community can result in unexpected outages and unhappy users. Therefore, it is recommended that a monitoring policy be established to report user file permissions and determine the action to be taken in accordance with site policy.

Default Value

Not applicable.

Notes

On some distributions the /sbin/nologin should be replaced with /usr/sbin/nologin.

References

None

CIS Controls

14.4 Protect Information With Access Control Lists - All information stored on systems shall be protected with file system, network share, claims, application, or database specific access control lists.

Profile

Level 1