How to Install Lynis Linux | Intro to Linux Security

We take server security very seriously, being datacenter hosts at IOFLOOD. When we need to ensure our servers are secure and compliant we like to install Lynis, as its security auditing tool helps us identify potential vulnerabilities. We have shared today’s article to aid our customers in enhancing the security of their dedicated bare metal servers.

In this tutorial, we will guide you on how to install the Lynis command on your Linux system. We will show you methods for both APT and YUM-based distributions, delve into compiling Lynis from source, installing a specific version, and finally, how to use the Lynis command and ensure it’s installed correctly.

So, let’s dive in and begin installing Lynis on your Linux system!

TL;DR: How To Install Lynis on Linux?

You can install Lynis Linux by cloning the Lynis repository from GitHub, git clone https://github.com/CISOfy/lynis, or by using a package manager such as apt-get, sudo apt-get install lynis. Here’s a quick example:

# Clone the Lynis repository

git clone https://github.com/CISOfy/lynis

# Navigate to the Lynis directory

cd lynis

# Run the Lynis audit system command

./lynis audit system

# Output:
# [Expected output from command]

This is a basic way to install Lynis on Linux, but there’s much more to learn about installing and using Lynis. Continue reading for more detailed information and advanced usage scenarios.

The Command to Install Lynis Linux

Lynis is an open-source security auditing tool. Used by system administrators, security professionals, and auditors, to evaluate the security defenses of their Linux and Unix-based systems. It runs on the host itself, so it performs more extensive security scans than vulnerability scanners.

APT Command to Install Lynis Linux

If you’re using a Debian-based distribution like Ubuntu, you can install Lynis from the standard repositories using the apt package manager. Here’s how:

# Update your package lists

sudo apt update

# Install Lynis

sudo apt install lynis

# Output:
# [Expected output from command]

This will install Lynis on your system. You can verify the installation by running lynis --check-update.

YUM Command to Install Lynis Linux

If you’re using a Red Hat-based distribution, you can use the yum package manager to install Lynis. Here’s how:

# Update your package lists

sudo yum check-update

# Install Lynis

sudo yum install lynis

# Output:
# [Expected output from command]

This will install Lynis on your system. You can verify the installation by running lynis --check-update.

In the next section, we’ll delve into more advanced usage of Lynis, including different options or flags you can use to customize your security audits.

Install Lynis Linux from Source Code

If the version of Lynis in your distribution’s repositories is outdated, or if you want to use the latest features, you can install Lynis from source. Here’s how:

# Clone the Lynis repository

git clone https://github.com/CISOfy/lynis

# Navigate to the Lynis directory

cd lynis

# Run the Lynis audit system command

./lynis audit system

# Output:
# [Expected output from command]

This will install the latest version of Lynis directly from the source code.

Install Other Versions of Lynis Linux

Different versions of Lynis may include new features, bug fixes, or improved compatibility with certain systems. Here’s how to install specific versions of Lynis from source and using package managers.

From Source

To install a specific version of Lynis from source, you can use the git checkout command to switch to a specific tag. Here’s an example:

# Clone the Lynis repository

git clone https://github.com/CISOfy/lynis

# Navigate to the Lynis directory

cd lynis

# Check out a specific version

git checkout 2.7.5

# Output:
# [Expected output from command]

This will install Lynis version 2.7.5 on your system.

Using APT

To install a specific version of Lynis using the apt package manager, you can specify the version number when installing. Here’s an example:

# Install a specific version of Lynis

sudo apt install lynis=2.7.5

# Output:
# [Expected output from command]

This will install Lynis version 2.7.5 on your system.

Using YUM

To install a specific version of Lynis using the yum package manager, you can specify the version number when installing. Here’s an example:

# Install a specific version of Lynis

sudo yum install lynis-2.7.5

# Output:
# [Expected output from command]

This will install Lynis version 2.7.5 on your system.

Version Comparison

Different versions of Lynis come with different features. Here’s a brief comparison:

Using and Verifying Lynis Install

Once you’ve installed Lynis, you can use it to conduct a security audit of your system. Here’s an example:

# Run a Lynis audit

./lynis audit system

# Output:
# [Expected output from command]

This will run a comprehensive security audit of your system. You can also verify that Lynis is installed correctly by checking its version number:

# Check Lynis version

lynis --version

# Output:
# Lynis version 2.7.5

This should display the version number of Lynis, confirming that it’s installed correctly.

Alternative Tools to Lynis Linux

While Lynis is a powerful tool for auditing system security, it’s not the only tool available. There are other alternatives out there that can complement Lynis or serve as a stand-in depending on your specific needs. Let’s explore some of them.

Tiger

Tiger is another security tool that can be used for security auditing. It’s a robust tool that can be used to identify system vulnerabilities and configuration issues.

To install Tiger, you can use the following commands:

# For Debian-based systems

sudo apt install tiger

# For Red Hat-based systems

sudo yum install tiger

# Output:
# [Expected output from command]

Once installed, Tiger can be run using the tiger command.

Rkhunter

Rkhunter (Rootkit Hunter) is a Unix-based tool that scans for rootkits, backdoors and possible local exploits. It operates by comparing SHA-1 hashes of important files with known good ones in online databases, searching for default directories of rootkits, and wrong file permissions for binaries.

Installation of Rkhunter varies depending on your distribution. Here’s an example:

# For Debian-based systems

sudo apt install rkhunter

# For Red Hat-based systems

sudo yum install rkhunter

# Output:
# [Expected output from command]

Once installed, you can run a system check using the rkhunter --check command.

Comparison of Lynis, Tiger, and Rkhunter

While all three tools provide system security auditing, they each have their strengths and weaknesses. Here’s a brief comparison:

While Lynis is a powerful and comprehensive tool, using it in conjunction with Tiger and Rkhunter can provide a more thorough security audit. As always, the best tool depends on your specific needs and the nature of your system.

Troubleshooting Lynis Linux Install

Like any software, you might encounter some issues when installing or using Lynis. Here are some common problems and their solutions.

Lynis: Command Not Found

If you see a lynis: command not found error after installation, it’s likely that Lynis isn’t in your system’s PATH. You can add it to your PATH using the following command:

# Add Lynis to your PATH

export PATH=$PATH:/path/to/lynis

# Output:
# [No output expected]

Replace /path/to/lynis with the actual path to the Lynis directory. After running this command, you should be able to use the lynis command.

Lynis: Permission Denied

If you see a lynis: permission denied error when trying to run Lynis, it’s likely that the Lynis script doesn’t have execute permissions. You can add execute permissions using the following command:

# Add execute permissions to the Lynis script

chmod +x /path/to/lynis/lynis

# Output:
# [No output expected]

Replace /path/to/lynis with the actual path to the Lynis directory. After running this command, you should be able to run Lynis.

Lynis: No Audit Results

If you run a Lynis audit but don’t see any results, it’s likely that Lynis isn’t configured correctly. You can check your Lynis configuration using the following command:

# Check Lynis configuration

lynis show settings

# Output:
# [Expected output from command]

This will display your Lynis settings. You can then adjust these settings as needed to ensure that Lynis is configured correctly.

Remember, troubleshooting is a normal part of using any software. Don’t be discouraged if you encounter issues. With patience and persistence, you’ll be able to get Lynis up and running on your system.

System Security Auditing in Linux

Before delving deeper into the usage of Lynis, it’s essential to understand what system security auditing is and why it’s crucial for Linux systems.

What is System Security Auditing?

System security auditing is the process of assessing and monitoring a system to ensure it complies with a set of established guidelines. It involves reviewing various system activities, including user behaviors, access controls, and system vulnerabilities.

# Example of checking system logs

cat /var/log/syslog | grep -i 'security'

# Output:
# [Expected output of security-related system logs]

In the above code block, we’re checking the system logs for any security-related entries. This is a simple example of what system security auditing might entail.

Why is it Important in Linux?

Linux, being an open-source operating system, is widely used in various environments, including servers, desktops, and embedded systems. While this makes Linux incredibly versatile, it also exposes it to various security threats.

Regular security audits help identify potential security risks before they become significant issues. This proactive approach is crucial in maintaining the integrity, confidentiality, and availability of the system and its data.

Role of Lynis Linux in Security

Lynis, as an advanced auditing tool, simplifies the process of system security auditing in Linux. It automates the process, checking for various potential issues, including insecure settings, configuration errors, and system vulnerabilities.

# Running a Lynis audit

./lynis audit system

# Output:
# [Expected output of a Lynis system audit]

In the above code block, we’re running a Lynis system audit. This command checks various aspects of the system and provides a detailed report, making it easier to understand the system’s current security status.

Understanding the importance of system security auditing and the role tools like Lynis play can help you better appreciate the value Lynis brings to maintaining your Linux system’s security.

Practical Uses of Lynis in Linux

While Lynis is a powerful tool for auditing system security, it’s just one piece of the puzzle. System administration and security involve many interconnected components, and understanding these can help you better secure your systems.

The Role of Intrusion Detection Systems

Intrusion Detection Systems (IDS) are designed to detect unauthorized access to a system. They work by monitoring system activity and user behaviors for any suspicious patterns.

Lynis can complement an IDS by providing a detailed security audit, which can help identify potential vulnerabilities that an intruder might exploit.

# Example of checking IDS logs

cat /var/log/snort/alert

# Output:
# [Expected output of IDS logs]

In the above code block, we’re checking the logs of Snort, a popular IDS. This can provide valuable insights into potential security threats.

The Importance of Firewall Configuration

Firewalls serve as the first line of defense in network security. They control the incoming and outgoing network traffic based on predetermined security rules.

Again, Lynis can help check for any misconfigurations in your firewall settings that could leave your system vulnerable.

# Example of checking firewall status

sudo ufw status verbose

# Output:
# [Expected output of firewall status]

In the above code block, we’re checking the status of UFW, a common firewall in Linux. This can help ensure that your firewall is properly configured.

Further Resources for Linux System Security

For those interested in delving deeper into system security, here are some resources that can help:

• The Linux System Administrator’s Guide: A comprehensive guide covering various aspects of system administration, including security.

• The CISOfy Knowledge Base: A collection of articles and guides related to Lynis and system security.

• The GNU/Linux Security Wikibook: A detailed guide focusing on various aspects of Linux security.

Recap: How to Install Lynis on Linux

In this comprehensive guide, we’ve journeyed through the process of installing and using Lynis on Linux. Lynis, a powerful tool for conducting comprehensive security audits for Unix and Linux systems, is a utility worth mastering for anyone serious about system security.

We began with the basics, learning how to install Lynis on Linux using package managers like APT and YUM. We then ventured into more advanced territory, exploring how to install Lynis from source code and how to install specific versions of Lynis. Along the way, we tackled common challenges you might face when using Lynis, such as command not found and permission denied errors, providing you with solutions and workarounds for each issue.

We also looked at alternative approaches to system security auditing, comparing Lynis with other tools like Tiger and Rkhunter. Here’s a quick comparison of these tools:

Whether you’re just starting out with Lynis or you’re looking to level up your system security skills, we hope this guide has given you a deeper understanding of Lynis and its capabilities. With its balance of comprehensiveness and ease of use, Lynis is a powerful tool for system security auditing on Linux. Keep exploring, keep learning, and happy auditing!