What’s system hardening?

Linux steps for starters


Most programs have confidential data that needs to be shielded. To safeguard this data, we need to safeguard our Linux platform. But to harden a Linux system? In the following article, we will pay this step by step. We begin with physical security measures to prevent people the system in the first location. Next is currently performing the installation the right way, therefore we’ve got a good base. We will apply a set of security measures that are shared. Your own server or desktop system should be protected, after we’re finished. Are you prepared? Let’s proceed with the first actions!

Table of Contents

Linux is secure by default, right?

What is system hardening?

Core fundamentals of system hardening

Principe of privilege


Reduction Security updates and patches Use strong passwords Bind processes to localhost Implement a firewall Keep things clean Safe settings

  1. Limit access
  2. Monitor your systems Perform system auditing server operating system

Additional hardening resourcesserver operating system

Linux is already secure by default, right?

Among the myths about Linux is that it is secure, as it isn’t vulnerable to viruses or other kinds of malware. This is partly true, as Linux uses the foundations of the first UNIX operating system. Processes are separated in what he or she is able to perform on the system, and a normal user is restricted. Linux is not perfectly protected by default. One reason is that the Linux distributions that bundle the applications as well as the GNU/Linux kernel. They must choose between performance, usability, and safety.

With the difficult choices that Linux distributions need to make, you can be certain of compromises. These compromises result in a lowered level of safety. That’s a fantasy that is definitely a. The Linux platform includes its fair share of rootkits backdoors, works, and sometimes even ransomware. That is one of the reasons why it is important to perform checking for compliance, safety auditing, and system hardening with technical instructions.

Picture of items that are connected to Linux system hardening, auditing, and compliance.

There are lots of aspects to Linux security, such as Linux platform hardening, auditing, and compliance.


To enhance the safety level of a system, we carry different kinds of measures. This uninstall some software components or might be the removal of an present system support.

System hardening is the procedure for performing the’right’ things. The goal is to improve the security level of this machine. There are lots of aspects to securing a system properly. The principles are similar for many operating systems. So that the system hardening process for servers and Linux desktop is special.

Core principles of system hardening

If we’d put a microscope on system hardening, we can divide the procedure into a few core principles. These include the principle of segmentation, least privilege, and loss.

Principe of privilege

The principle of least privileges ensures that you give users and procedures the bare minimum of permission to do their job. It’s much like granting a visitor access. You could provide whole access such as all areas. The other option is to only allow your guest in the place where they will need to be to get one floor. The choice is easy, right?


When read-only access Is Sufficient, do not give write permissions

Don’t enable executable code in memory areas that are flagged as data segments

Don’t run programs because the root user, instead use a non-privileged user account


The next principle is that you split larger areas into smaller ones. We have split it if we look at that building again. Each floor may be divided into different zones. Maybe you visitor is only allowed at the blue corner. This principle would apply to memory usage if we translate this to Linux security. Each procedure can access their own memory sections.


This principle aims to remove something that isn’t strictly required for the machine to work. It appears like the principle of least privilege, however focuses on preventing something in the first location. A procedure that doesn’t need to run, should be stopped. Similar for user account or information that is no longer being used.

Review of hardening steps

Install security upgrades and patches

Bind procedures to localhost

Employ a firewall

Keep things fresh

Limit access

Monitor your systems

Create backups (and test!)

Perform program auditing Security updates and patches

Most weaknesses in programs are caused by defects in applications. These defects we predict vulnerabilities. Good care for software patch management help with decreasing lots of the related risks. Of installing updates the activity has a risk, particularly when starting with the security patches . Most Linux distributions have the option to restrict what packages you would like to upgrade (all, security only, per bundle ). Make sure your security upgrades are installed. It goes without saying, prior to starting implementing something, test it on a (virtual) evaluation system.

Depending on your Linux distribution there could be a way to apply security patches automatically, like unattended updates on Debian and Ubuntu. This makes software patch management a lot easier!

  1. Use strong passwords

The main gateway into a system is by simply logging in as a user using the password of that account. Strong passwords make it even more challenging for tools to imagine the password and allow men and women walk in via the front door. A strong password consists of a variety of characters (alphanumeric, numbers, special like percent, space, as well as Unicode characters). Bind procedures to localhost

Not all solutions need to be accessible via the system. By way of instance, when running a local example of MySQL in your web server, allow it only listen on a local socket or link to localhost ( Configure your program to link via this speech, which is typically the default.

  1. Implement a firewall

Just enabled traffic should in an ideal situation reach your system. To make this happen, implement a firewall solution like the more recent nftables, or iptables.

When developing a policy for your firewall, consider using a”deny all, let some” policy. So you deny all traffic by default, then define what kind of traffic you want to allow. This is useful to protect against.

Useful reads:

  1. Keep things clean

Everything installed onto a system which doesn’t belong there can only negatively affect your machine. It will also increase your copies (and restore instances ). Or they might contain vulnerabilities. A clean system is often a protected and more healthy system. Minimalization is a great method in the procedure for Linux hardening.

Actionable jobs comprise:

Delete unused bundle

Clean up old home directories and remove the consumers

  1. Secure configurations

Most programs have one or more safety measures available to protect against some forms of risks to the software or system. Have a look at the man page for any choices and test these choices carefully.

  1. Limit access

Only allow access into this machine for authorized users. Does someone really want access or are methods possible to give the consumer what he or she wants? Monitor your systems

Many intrusions are undetected, because of absence of observation. Employ system monitoring and execute monitoring. By way of instance, this Linux audit framework’s use increased detection levels of events. Create backups (and test!)

Regularly make a backup of system data. This can prevent information loss. More significant, test your copies. Using a backup is nice, but it is!

Backups can be carried out using existing system tools like tar and scp. Another alternative to spare bandwidth is currently synchronizing data. If you rather want to use a program, contemplate Bacula or Amanda. Perform system auditing

Lynis (Linux/Unix auditing tool) screenshot

You can’t properly protect a system if you don’t measure it.

Utilize a safety tool like Lynis to execute a normal audit of your system. Any findings stored in a data file for further analysis and are revealed on the display. With a comprehensive log record, plan actions that are next for system hardening and it enables to use all available data.

Lynis runs on almost all Linux programs or Unix tastes. It needs a shell that is normal. Root permissions are favored, yet not mandatory. The safety tool is free to use and open source software (FOSS).