Cis Ubuntu2004 V300 6 3 3 1

---
name: cis-ubuntu2004-v300-6-3-3-1
description: "Ensure changes to system administration scope (sudoers) is collected"
category: cis-logging
version: "3.0.0"
author: cyberstrike-official
tags: [cis, ubuntu, linux, ubuntu-20.04, auditing, auditd]
cis_id: "6.3.3.1"
cis_benchmark: "CIS Ubuntu Linux 20.04 LTS Benchmark v3.0.0"
tech_stack: [ubuntu, linux]
cwe_ids: []
chains_with: []
prerequisites: []
severity_boost: {}
---

# 6.3.3.1 Ensure changes to system administration scope (sudoers) is collected (Automated)

## Profile

- Level 2 - Server
- Level 2 - Workstation

## Description

Monitor scope changes for system administrators. If the system has been properly configured to force system administrators to log in as themselves first and then use the `sudo` command to execute privileged commands, it is possible to monitor changes in scope. The file `/etc/sudoers`, or files in `/etc/sudoers.d`, will be written to when the file(s) or related attributes have changed. The audit records will be tagged with the identifier "scope".

## Rationale

Changes in the `/etc/sudoers` and `/etc/sudoers.d` files can indicate that an unauthorized change has been made to the scope of system administrator activity.

## Audit Procedure

### Command Line

On disk configuration - Run the following command to check the on disk rules:

```bash
# awk '/^ *-w/ \
&&/\/etc\/sudoers/ \
&&/ +-p *wa/ \
&&(/ key= *[!-~]* *$/||/ -k *[!-~]* *$/)' /etc/audit/rules.d/*.rules
```

Verify the output matches:

```
-w /etc/sudoers -p wa -k scope
-w /etc/sudoers.d -p wa -k scope
```

Running configuration - Run the following command to check loaded rules:

```bash
# auditctl -l | awk '/^ *-w/ \
&&/\/etc\/sudoers/ \
&&/ +-p *wa/ \
&&(/ key= *[!-~]* *$/||/ -k *[!-~]* *$/)'
```

Verify the output matches:

```
-w /etc/sudoers -p wa -k scope
-w /etc/sudoers.d -p wa -k scope
```

## Expected Result

Both on disk and running configuration should show the sudoers watch rules with key "scope".

## Remediation

### Command Line

Edit or create a file in the `/etc/audit/rules.d/` directory, ending in `.rules` extension, with the relevant rules to monitor scope changes for system administrators.

Example:

```bash
# printf "
-w /etc/sudoers -p wa -k scope
-w /etc/sudoers.d -p wa -k scope
" >> /etc/audit/rules.d/50-scope.rules
```

Merge and load the rules into active configuration:

```bash
# augenrules --load
```

Check if reboot is required:

```bash
# if [[ $(auditctl -s | grep "enabled") =~ "2" ]]; then printf "Reboot required to load rules\n"; fi
```

## References

1. NIST SP 800-53 Rev. 5: AU-3

## CIS Controls

| Controls Version | Control                                                         | IG 1 | IG 2 | IG 3 |
| ---------------- | --------------------------------------------------------------- | ---- | ---- | ---- |
| v8               | 8.5 Collect Detailed Audit Logs                                 |      | X    | X    |
| v7               | 4.8 Log and Alert on Changes to Administrative Group Membership |      | X    | X    |

MITRE ATT&CK Mappings: T1562, T1562.006 / TA0004 / M1047