Audit Your System for Security Vulnerabilities with Lynis (with examples)

Lynis is a powerful system and security auditing tool that helps to identify potential security vulnerabilities in your Linux system. In this article, we will explore three different use cases of the Lynis command and provide examples for each case.

Use Case 1: Check that Lynis is up-to-date

The first use case involves checking if Lynis is up-to-date. This is important as new vulnerabilities can be constantly discovered, and maintaining an updated version of Lynis ensures that the tool can accurately identify these vulnerabilities.

Here is the code to check if Lynis is up-to-date:

sudo lynis update info

• Motivation: It is essential to keep the Lynis tool up-to-date to benefit from the latest security checks and improvements.

• Explanation: The lynis update info command is used to retrieve information about the latest version of Lynis and compare it with the currently installed version.

• Example Output:

Lynis file: /usr/sbin/lynis
Lynis version: 3.0.5
Latest version available: 3.1.0

The example output shows that the current version of Lynis installed on the system is 3.0.5, while the latest available version is 3.1.0.

Use Case 2: Run a Security Audit of the System

The second use case involves running a security audit of the system. This comprehensive audit will scan various aspects of your Linux system, including configuration files, installed software, and common security settings.

Here is the code to run a security audit of the system:

sudo lynis audit system

• Motivation: Security audits help to identify vulnerabilities and misconfigurations in your system, allowing you to take appropriate actions to mitigate potential risks.

• Explanation: The lynis audit system command initiates a security audit of the entire system. Lynis will scan different parts of the system and provide a detailed report highlighting any security issues found.

• Example Output:

[+] Initializing program
[+] Detecting OS...
[+] Collecting system information...
[+] Detecting installed programs...
[+] Checking for security and vulnerability information...
[+] Initializing tests...
[+] Testing system parts...
[+] Writing results to report...
[+] Report written to: /var/log/lynis.log
[+] Done with tests!

The example output demonstrates the progress of the security audit as each step is performed by Lynis. Once completed, the audit results are saved in the /var/log/lynis.log file.

Use Case 3: Run a Security Audit of a Dockerfile

The third use case focuses on running a security audit specifically for a Dockerfile. Dockerfiles contain instructions to build Docker images, and it is crucial to ensure that they are free from security vulnerabilities.

Here is the code to run a security audit of a Dockerfile:

sudo lynis audit dockerfile path/to/dockerfile

• Motivation: With the increasing popularity of containerization, securing Dockerfiles is essential to prevent potential security breaches and ensure the integrity of the resulting Docker images.

• Explanation: The lynis audit dockerfile command allows you to perform a security audit specifically for a Dockerfile. You need to specify the path to the Dockerfile that you want to audit.

• Example Output:

[+] Initializing program
[+] Analyzing Dockerfile: /path/to/dockerfile
[+] Collecting system information...
[+] Detecting installed programs...
[+] Loading custom profiles...
[+] Analyzing Dockerfile contents...
[+] Running tests...
[+] Writing results to report...
[+] Report written to: /var/log/lynis-dockerfile.log
[+] Done with tests!

The example output demonstrates the steps performed by Lynis while auditing the specified Dockerfile. Once completed, the audit results are saved in the /var/log/lynis-dockerfile.log file.

Conclusion

Lynis is a valuable tool for auditing the security of your Linux system. By utilizing the provided examples, you can perform regular security audits, ensure that Lynis is up-to-date, and evaluate the security of Dockerfiles. Taking these steps will help you identify and address potential vulnerabilities, improve the overall security posture of your system, and protect against potential security threats.