# Ensure cryptographic mechanisms are used to protect the integrity of audit tools

Necessity: The integrity of audit tools is paramount for a secure system. If an attacker can modify audit binaries (e.g., auditctl, aureport), they can disable logging, alter logs to hide their activities, or prevent detection altogether. This undermines the entire security monitoring and incident response framework. Using a cryptographic file integrity checker like AIDE ensures that any unauthorized modification to these critical tools is detected, preserving the trustworthiness of the audit system.

Auditing and Remediation: The audit script verifies that the AIDE package is installed, which is the mechanism used to protect file integrity. The remediation script installs the AIDE package, which provides the necessary cryptographic tools, and performs the initial setup to create a baseline database of file signatures against which future checks will be compared.

Recommended State Rationale: For this control, the state is binary; the tool is either installed or it is not. Therefore, the Basic, Moderate, and Strict levels all recommend 'Installed'. The presence of a file integrity monitoring tool is a foundational security best practice (mandated by standards like CIS Benchmarks and PCI DSS). There is no less-secure but acceptable alternative. The true strictness of the implementation would depend on the AIDE configuration rules and the frequency of integrity checks, but the prerequisite for any level of protection is the tool's installation.

## Recommended State Configuration

| Security Level | Value |
|----------------|-------|
| **Basic** | `['Installed']` |
| **Moderate** | `['Installed']` |
| **Strict** | `['Installed']` |
| **Type** | `ENUM` |

## Audit Script Working

bash script that checks if the 'aide' (Advanced Intrusion Detection Environment) package is installed. The script should output 'Installed' if the package is present, and 'Not Installed' otherwise. The output must contain only the status string, with no additional text.

## Remediation Script Working

bash script that accepts one positional argument: 'Installed'. If the argument is 'Installed', the script must install the 'aide' package using 'apt-get install -y aide'. After a successful installation, it must initialize the AIDE database. The script should return 'true' on success and 'false' on failure.

