Linux Server Hardening Guide

Since Kali Linux is a Debian-based Linux distribution, you can use the Linux hardening tips above to address the security weaknesses in Kali Linux systems. This is very useful if you want to disallow users to use same old passwords. But, we’ve just scratched the surface of Linux Hardening—there are a lot of complex, nitty-gritty configurations. To learn more about how to harden your Linux servers for better security, check out these Linux courses. The list can go on and on, but these should be enough to start with. For example, some companies add banners to deter attackers and discourage them from continuing further.

You need to decide what security measures are needed, but remember, this isn’t a one-time job. To take SSH security to the next level, you may also enable two-factor authentication. In this approach, you receive a one-time password on your mobile phone, email or through a third-party aunthentication app. Before you go for this approach, make sure that you have added your own public key to the server and it works. Otherwise, you’ll lock yourself out and may lose access to the remote server specially if you are using a cloud server like Linode where you don’t have physical access to the server. To thwart SSH bruteforce attacks, you can use a security tool like Fail2Ban.

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I have written a detailed introductory guide on using Fail2Ban which you should read. When it comes to security, you should follow the principal of least privilege. Newer SSH versions automatically have SSH protocol 2 enabled but no harm in double checking it. Some older linux hardening and security lessons SSH version might still have SSH protocol 1 available. A good way to monitor log activity is to use third-party log monitoring software, such as LogWatch, for log analysis and notifications. Notifications and daily digests can be sent to administrators via email.

Linux Server Hardening in 15 Steps

In this short post, we covered many important configurations for Linux security. But, we’ve just scratched the surface of Linux hardening—there are a lot of complex, nitty-gritty configurations. To learn more about how to harden your Linux servers for better security, check out my courses on Pluralsight. Portioning disks gives you the opportunity of performance and security in case of a system error.

Configure and install a fail2ban firewall

These server hardening checklist items are broad strokes that apply to Windows, Linux, and other types of servers. If you want a detailed breakdown, the NIST and CIS benchmarks have the resources you need. Generating a PEM (Privacy Enhanced Mail) key and establishing a secure connection to a Linux server is a fundamental process in securing remote access. PEM keys, often used for SSH (Secure Shell) authentication, provide a robust alternative to password-based logins.

  • The subsequent connection, validated by the PEM key pair, ensures a seamless and secure interaction with the Linux server, contributing to a robust security posture.
  • Time invested going through steps like the ones laid out will return dividends in the future.
  • One of the most popular implementations of SCAP is OpenSCAP and it is very helpful for vulnerability assessment and as a hardening helper.
  • Similarly for Linux Mint, as an Ubuntu-derived Desktop Linux platform, the same hardening procedures used for Debian-Linux should be adopted.
  • They can help greatly in finding new techniques to further increase your security defenses.

Useful for system hardening are auditing tools as they perform a health scan of the system and define room for improvement. Additionally useful are tools that actually also implement some of the hardening measures. Each file is assigned an owner and a group and a set of file permissions.

Utilize Backups and Test Them Often

Still, don’t be scared and test your changes first on a virtual system where you always have root access. Create an additional test user and log in with that, to help with testing. After the first installation steps, the creation of a user account is performed.

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