How to secure Linux systems Auditing, Hardening and Security

This way you gain the best possible understanding of the subject and make the right decision. After all, you have to decide what is best for your Linux systems when it comes to hardening them. So whatever you encounter on other websites or in this particular checklist, follow the saying Trust, but verify. There is the risk that a change can have unexpected consequences. The more changes, the bigger the risk that something will no longer work. Kernel hardening involves securing the Linux kernel, the core of the operating system, against various types of attacks.

So a web server would typically allow incoming HTTPS requests to port 443/TCP. Most Linux distributions use the modular framework named PAM, which is short for pluggable authentication module. The framework allows configuring most of the settings related to authentication, such as where to check that a user or account exists. It also includes the configuration related to password strength, two-factor authentication, and even protection mechanisms against brute-force attacks. Secure SSH access by using key-based authentication, changing the default port, disabling root login, and using tools like Fail2Ban to prevent brute force attacks. The irony is that now our information security platforms are creating new security risks.

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For technical teams, it might be good to have strict rules on the usage of accounts. For example, is a personal account allowed to run software on a system for more than a single task? Too often, a developer or system administrator starts a process with their own user, instead of a functional account.

• Without applying the security hardening measure described, the probability is much higher than my attacker will have what they need be successful in their cyber assault.
• You’ll also learn how to enforce strong passwords and manage account and password expirations.
• It helps to find missing security controls, so additional system hardening measures can be applied to systems.
• There is the risk that a change can have unexpected consequences.
• After the installation of a Linux-based system, so-called system hardening is needed.

We’ll cover how permissions work in detail, including special modes, file attributes, and ACL’s. You’ll also learn what rootkits are, how to detect them, and how to remove them. In the networking section, Linux Hardening and Security Lessons you’ll learn how to secure network services that run on Linux systems. We’ll cover file system security and how permissions work in detail, including special modes, file attributes, and ACLs.

Authentication

This way you always have the option to go back to a previous configuration, if for some reason things fail. In the world of Bash scripting, scheduling tasks to run at specific times is a common need…. Get weekly Linux news, tutoials, tips & tricks, and other useful information related to Linux and Open source in your INBOX.

• We start by taking a look at Linux security in general before moving on to physical security and the countermeasures you can employ to protect your hardware.
• A mail server usually has this port blocked and instead allow connections to port 25/TCP.
• Bring your own system configured according to these instructions.
• It also includes the configuration related to password strength, two-factor authentication, and even protection mechanisms against brute-force attacks.

While it looks innocent, it provides attackers with valuable data. It is not that hard to obtain the operating system that is used. When also learning about the used software components, it becomes much easier to see if there are specific attacks available. Hiding software banners and version numbers will also stop most automated attack scripts, as they often go on the hunt for a specific version.

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Most package managers on Linux can show the available updates. When adding new security measures, there is a lot to chose from. Let’s look at some of the available technical measures you can take. The following is a list of security and hardening guides for several of the most popular Linux distributions. To get the most out of this course, you should already have a good working knowledge of Linux.

It ensures that even if data is intercepted or accessed by unauthorized persons, it remains unreadable and secure. 2FA adds an extra layer of security by requiring two forms of identification before granting access. In Linux, it can be implemented using tools like Google Authenticator or Duo Security. ACLs provide a more flexible permission mechanism for file systems. They allow you to specify granular permissions for users and groups beyond the traditional file permission model.