Introduction to methods to protect Linux system security

In today's environment, it is very important to ensure the security of Linux-based systems. But, you have to know how to do it. A simple anti-malware software is not enough, you need other measures to work together. So how to ensure the security of Linux systems? Today, the editor will summarize nine common methods for you to protect the security of Linux systems. I hope it can help you.

　1. Using SELinux

SELinux is used to harden the security of Linux. With it, users and administrators can have more control over access control. SELinux adds finer-grained control to access control. Unlike the permissions that can only specify who can read, write, or execute a file, SELinux allows you to specify who can delete links, only append, move a file, and more. (LCTT translation annotation: Although the NSA has also contributed a lot of code to SELinux, there is currently no evidence that SELinux has potential backdoors)

　2 Disable unused services and applications

Generally speaking, users Most of the time less than half of the services and applications on their system are used. However, these services and applications will still run, which can attract attackers. Therefore, it is best to stop these unused services. (LCTT translation annotation: Or simply do not install services that are not used, so that you don’t have to pay attention to whether they have security vulnerabilities and need to be upgraded.)

　3 Subscribe to the vulnerability alert service

Security flaws Not necessarily on your operating system. In fact, vulnerabilities are often found in installed applications. To avoid this problem, you must keep your application updated to the latest version. Additionally, subscribe to a vulnerability alert service such as SecurityFocus.

　4 Using Iptables

　What is Iptables? This is an application framework that allows users to build a powerful firewall for the system. Therefore, to improve your security protection capabilities, you need to learn how to make a good firewall and how to use the Iptables framework.

　5 Check System Logs

Your system logs tell you what activity occurred on your system, including whether an attacker successfully entered or attempted to access the system. Always be vigilant, this is your first line of defense, and regular monitoring of system logs is to guard this line of defense.

　6 Consider using port knocking

Setting up port knocking is a good way to establish a secure connection to the server. The general approach is to send specific packets to the server to trigger a response/connection from the server (open the firewall). Port knocking is a good defensive measure for systems with open ports.

　7. Deny all by default

Firewalls have two ideas: one is to allow every point of communication, and the other is to deny all access and prompt you for permission. The second one is better. You should only allow in those communications that are important. (LCTT translation annotation: the default permission policy and the default prohibition policy. In the former, you need to specify what should be prohibited, and everything else is allowed; in the latter, you need to specify what can be allowed, and everything else is prohibited.)

8. Use full disk encryption

Encrypted data is harder to steal and sometimes impossible to steal, which is why you should encrypt your entire drive. After using this method, if someone enters your system, he will have a headache after seeing the encrypted data. According to some reports, most data loss results from machine theft.

　9. Use an intrusion detection system

An intrusion detection system, or IDS, allows you to better manage communications and attacks on your system. Snort is currently recognized as the best IDS on Linux.

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