| name | CIS Ubuntu 14.04 LTS - 5.4.2 Ensure system accounts are non-login |
| description | Verify system accounts have non-login shells and are locked to prevent interactive access |
| category | cis-os-hardening |
| version | 2.1.0 |
| author | cyberstrike-official |
| tags | ["cis","ubuntu","ubuntu-14.04","level-1","scored","user-accounts"] |
| cis_id | 5.4.2 |
| cis_benchmark | CIS Ubuntu Linux 14.04 LTS Benchmark v2.1.0 |
| tech_stack | ["ubuntu","linux"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | medium |
5.4.2 Ensure system accounts are non-login (Scored)
Profile Applicability
- Level 1 - Server
- Level 1 - Workstation
Description
There are a number of accounts provided with Ubuntu that are used to manage applications and are not intended to provide an interactive shell.
Rationale
It is important to make sure that accounts that are not being used by regular users are prevented from being used to provide an interactive shell. By default, Ubuntu sets the password field for these accounts to an invalid string, but it is also recommended that the shell field in the password file be set to /usr/sbin/nologin. This prevents the account from potentially being used to run any commands.
Audit Procedure
Run the following script and verify no results are returned:
egrep -v "^\+" /etc/passwd | awk -F: '($1!="root" && $1!="sync" && $1!="shutdown" && $1!="halt" && $3<1000 && $7!="/usr/sbin/nologin" && $7!="/bin/false") {print}'
Expected Result
No output should be returned.
Remediation
Set the shell for any accounts returned by the audit script to /usr/sbin/nologin:
usermod -s /usr/sbin/nologin <user>
The following script will automatically set all user shells required to /usr/sbin/nologin and lock the sync, shutdown, and halt users:
#!/bin/bash
for user in `awk -F: '($3 < 1000) {print $1 }' /etc/passwd`; do
if [ $user != "root" ]; then
usermod -L $user
if [ $user != "sync" ] && [ $user != "shutdown" ] && [ $user != "halt" ]; then
usermod -s /usr/sbin/nologin $user
