Cis Ubuntu1204 V110 8 1 11

---
name: cis-ubuntu1204-v110-8-1-11
description: "Collect Unsuccessful Unauthorized Access Attempts to Files"
category: cis-os-hardening
version: "1.1.0"
author: cyberstrike-official
tags: [cis, ubuntu, 12.04, linux, logging, auditd, access, unauthorized, eacces, eperm]
cis_id: "8.1.11"
cis_benchmark: "CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0"
tech_stack: [ubuntu, linux]
cwe_ids: []
chains_with: []
prerequisites: []
severity_boost: {}
---

# 8.1.11 Collect Unsuccessful Unauthorized Access Attempts to Files (Scored)

## Profile Applicability

- Level 2

## 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 nonprivileged user (auid >= 500), 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."

## 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.

## Audit Procedure

### Using Command Line

On 64 bit systems, perform the following command and ensure the output is as shown to determine if there are unsuccessful attempts to access files:

```bash
grep access /etc/audit/audit.rules
```

On 32 bit systems:

```bash
grep access /etc/audit/audit.rules
```

## Expected Result

For 64 bit systems:

```
-a always,exit -F arch=b64 -S creat -S open -S openat -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b32 -S creat -S open -S openat -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b64 -S creat -S open -S openat -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -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>=500 -F auid!=4294967295 -k access
```

For 32 bit systems:

```
-a always,exit -F arch=b32 -S creat -S open -S openat -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -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>=500 -F auid!=4294967295 -k access
```

## Remediation

### Using Command Line

For 64 bit systems, add the following lines to the `/etc/audit/audit.rules` file:

```bash
-a always,exit -F arch=b64 -S creat -S open -S openat -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b32 -S creat -S open -S openat -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
-a always,exit -F arch=b64 -S creat -S open -S openat -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -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>=500 -F auid!=4294967295 -k access
# Execute the following command to restart auditd
pkill -HUP -P 1 auditd
```

For 32 bit systems, add the following lines to the `/etc/audit/audit.rules` file:

```bash
-a always,exit -F arch=b32 -S creat -S open -S openat -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -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>=500 -F auid!=4294967295 -k access
# Execute the following command to restart auditd
pkill -HUP -P 1 auditd
```

## Default Value

By default, unsuccessful unauthorized access attempts to files are not audited.

## References

- CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0

## Profile

Level 2 - Scored