Here are some Linux security-related resources to help you cope if your Linux servers had been hacked, to help you with prevention and some useful tools you should know.

* If you haven’t read our power guide: “How to Investigate Suspected Break-in Attempts in Linux?” we recommend you to do so right now.

How to deal with a compromised Linux system

1. A great article from the Linux documentation project on what to do during and after a break-in: https://www.tldp.org/HOWTO/Security-HOWTO/after-breakin.html

2. Some high-level steps for dealing with a compromised Linux sever: https://linux-audit.com/dealing-with-a-compromised-linux-system/

How to harden a Linux server’s security

1. A really good tutorial from nixCraft on hardening Linux security: https://www.cyberciti.biz/tips/linux-security.html

2. Another great resource from nixCraft on SSH best practice: https://www.cyberciti.biz/tips/linux-unix-bsd-openssh-server-best-practices.html

3. How to secure your Linux server with TripWire: https://opensource.com/article/18/1/securing-linux-filesystem-tripwire

4. Dr. Dobb’s guide to the Advanced Intrusion Detection (AIDE) tool: http://www.drdobbs.com/aide-to-the-rescue-an-open-source-sec/199101554

5. A guide to SELinux: https://www.digitalocean.com/community/tutorial_series/an-introduction-to-selinux-on-centos-7

How to scan and audit Linux servers for possible security holes

1. How to audit Linux vulnerabilities: https://linux-audit.com/linux-vulnerabilities-explained-from-detection-to-treatment/

2. Five tools to scan a Linux server for Malware: https://www.tecmint.com/scan-linux-for-malware-and-rootkits/

3. Lynis – an open source tool for auditing, security hardening and checking compliance: https://cisofy.com/lynis/

4. DigitalOcean’s tutorial on how to perform security audit with Lynis on Ubuntu: https://www.digitalocean.com/community/tutorials/how-to-perform-security-audits-with-lynis-onubuntu-16-04

5. 15 open source security tools: https://hackertarget.com/10-open-source-security-tools/

Security vulnerability lists

1. Ubuntu security notices: https://usn.ubuntu.com/

2. RedHat security updates page: https://access.redhat.com/security/security-updates/#/

3. Top 5 security vulnerabilities of 2018: https://resources.whitesourcesoftware.com/blog-whitesource/top-5-linux-kernel-vulnerabilities-in-2018

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