cis-ubuntu1604-v200-1-1-22

name	cis-ubuntu1604-v200-1-1-22
description	Ensure sticky bit is set on all world-writable directories
category	cis-storage
version	2.0.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-16.04","filesystem","sticky-bit","world-writable","permissions"]
cis_id	1.1.22
cis_benchmark	CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

Ensure sticky bit is set on all world-writable directories

Description

Setting the sticky bit on world writable directories prevents users from deleting or renaming files in that directory that are not owned by them.

Rationale

This feature prevents the ability to delete or rename files in world writable directories (such as /tmp) that are owned by another user.

Impact

None noted.

Audit Procedure

Command Line

# Run the following command to verify no world writable directories exist without the sticky bit set:
df --local -P | awk '(if (NR!=1) print $6}' | xargs -I '{}' find '{}' -xdev -type d \( -perm -0002 -a ! -perm -1000 \) 2>/dev/null

Expected Result

No output should be returned.

Remediation

Command Line

# Run the following command to set the sticky bit on all world writable directories:
df --local -P | awk '{if (NR!=1) print $6}' | xargs -I '{}' find '{}' -xdev -type d \( -perm -0002 -a ! -perm -1000 \) 2>/dev/null | xargs -I '{}' chmod a+t '{}'

Default Value

The sticky bit is set on /tmp by default.

References

• CIS Controls Version 7 - 5.1 Establish Secure Configurations: Maintain documented, standard security configuration standards for all authorized operating systems and software.

Profile

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