cis-ubuntu1604-v200-4-1-10

name	cis-ubuntu1604-v200-4-1-10
description	Ensure unsuccessful unauthorized file access attempts are collected
category	cis-logging
version	2.0.0
author	cyberstrike-official
tags	["cis","ubuntu","linux","ubuntu-16.04","auditd","logging"]
cis_id	4.1.10
cis_benchmark	CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0
tech_stack	["ubuntu","linux"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - Control 4.1.10

Profile

• Level: 2 - Server
• Level: 2 - Workstation
• Assessment Status: Automated

Description

Monitor for unsuccessful attempts to access files. The parameters below are associated with system calls that control creation (creat), opening (open, openat) and truncation (truncate, ftruncate) of files. An audit log record will only be written if the user is a non-privileged user (auid >= 1000), is not a Daemon event (auid=4294967295) and if the system call returned EACCES (permission denied to the file) or EPERM (some other permanent error associated with the specific system call). All audit records will be tagged with the identifier "access."

Note: Reloading the auditd config to set active settings requires the auditd service to be restarted, and may require a system reboot.

Rationale

Failed attempts to open, create or truncate files could be an indication that an individual or process is trying to gain unauthorized access to the system.

Impact

None.

Audit Procedure

Command Line

On a 32 bit system:

Run the following command to verify the rules are contained in a .rules file in the /etc/audit/rules.d/ directory:

grep access /etc/audit/rules.d/*.rules

Verify output matches:

-a always,exit -F arch=b32 -S creat -S open -S openat -S truncate -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=4294967295 -k access
-a always,exit -F arch=b32 -S creat -S open -S openat -S truncate -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=4294967295 -k access

Run the following command to verify that rules are in the running auditd config:

auditctl -l | grep access

Verify output matches:

-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat -F exit=-EACCES -F auid>=1000 -F auid!=-1 -F key=access
-a always,exit -F arch=b32 -S open,creat,truncate,ftruncate,openat -F exit=-EPERM -F auid>=1000 -F auid!=-1 -F key=access

On a 64 bit system:

Run the following command to verify the rules are contained in a .rules file in the /etc/audit/rules.d/ directory:

grep access /etc/audit/rules.d/*.rules

Verify output matches: