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10 Tips to Harden Your Linux System Security
Security

10 Tips to Harden Your Linux System Security

Most people use Windows or macOS, which leaves them vulnerable to popular exploits. But when you want to take things into your own hands, you go to Linux. No matter which operating system you pick, there’s an inherent security flaw. And hardening Linux security is a must. Bad actors, cybercriminals, and hackers will try to lure you into scams. That’s why you need to use these tips to improve your Linux security.

1. Minimize Software Installation

Let’s be honest. You don’t really need all sorts of software and web services installed on Linux. You can function pretty well with the basics. Every new program on your device adds unnecessary vulnerabilities. Review all the software packages you have installed and delete the ones you don’t use or feel are unnecessary.

2. Keep the Kernel Updated

Security patches are an absolute must. Linux allows easy updates to newer versions, and you have all the tools to keep everything up to date. As soon as you see a security update, apply it. You can use the RPM package to keep both software and the kernel updated at all times.

3. Be Wary of Packet Sniffers

A lot of Linux users use rsh, telnet, and FTP commands. If someone is on the same network, they can catch all those commands and even listen in to your usernames and passwords. Make the switch and start using FTPS (FTP over SSL), SFTP, or OpenSSH. These add more encryption to the commands, and you can even remove insecure services.

4. Use One Network Per VM or System Instance

Hackers will do their best to exploit you. Let’s say they succeed and get to Apache flow. The hacker will gain control over the entire server, your emails, and your database. The easiest way to stop this from happening is to run a different network on every VM instance and on separate servers. That way, you limit the breach and localize it.

5. Use Security Extensions

The Linux kernel has a firewall that checks the network traffic that goes into and through your server. It’s the Netfilter subsystem, but it’s not enough to protect everything. You need to be on top of any compromised programs and malicious code. There are security extensions like SELinux that can enforce limitations on programs and the network.

6. Use Strong Passwords and Accounts

Usually, multiple people will use the same Linux server, so it’s important to have multiple accounts and maintain them. You need to adhere to a strong password policy that includes numbers, letters, and special characters. Ensure the passwords are easy to remember but longer than 12 characters. You can also use a tool like John the Ripper to see if someone uses a weak password on your server.

7. Set Up Password Aging

Use a change command to set a timeframe after which you have to change your password. You can enable or disable this option, but it’s much better to set up a few more parameters. Set a maximum date for each password, something like four months. Set a warning to the user that their password will expire after three months, which will remind them to change it. Finally, you can set an expiry for a specific user, after which they won’t be able to use the login.

8. Hide Your Personal Information

If you’ve suffered a data breach, hackers can do everything from emptying your bank account to stealing your identity and hacking all your online accounts. After a data breach, hackers usually run to the dark web and post your information for sale. There are a couple of things you can do to see if your information is there:

  • Run a dark web scan.
  • Enable 24/7 dark web monitoring.
  • Check the recent data breaches.
  • Look for signs that you’ve been hacked.
  • Notice red flags about getting your identity stolen.

9. Use Kerberos

If you want to make high-risk tasks like inter-system file copying, remote copy, and remote logins safer, you need to use Kerberos. It’s a third-party service that performs authentications, and everyone who is an unauthorized user who wants to log in or gather passwords will be thwarted.

10. Configure Auditing and Logging

Logs and audits will show you all the attempts cybercriminals make to crack or hack your device. In general, the syslog keeps the data in /var/log/ directory. You can also check various attacks that happen due to software misconfiguration.

Additional Linux Security Tips

  1. Use Two-Factor Authentication (2FA) Implement 2FA for user logins, especially for SSH access. This adds an extra layer of security beyond just passwords.
  2. Disable Root Login Prevent direct root logins and use sudo for administrative tasks. This reduces the risk of full system compromise if credentials are stolen.
  3. Implement File System Security Use appropriate file permissions and consider implementing access control lists (ACLs) for more granular control over file access.
  4. Configure and Use a Firewall Set up and maintain a firewall like iptables or ufw to control incoming and outgoing network traffic.
  5. Use Intrusion Detection/Prevention Systems (IDS/IPS) Implement tools like Snort or OSSEC to monitor for and respond to potential security threats in real-time.
  6. Encrypt Sensitive Data Use disk encryption tools like LUKS for full-disk encryption, especially on mobile devices.
  7. Regularly Backup Your System Maintain up-to-date backups of your system and important data, preferably in multiple locations including off-site.
  8. Monitor System Logs Regularly review system logs for unusual activities or potential security breaches. Consider using log analysis tools for larger systems.
  9. Disable Unnecessary Services Turn off any network services or daemons that aren’t actively needed to reduce potential attack vectors.
  10. Use Secure Shell (SSH) Keys Instead of password-based authentication for SSH, use SSH keys which are more secure and resistant to brute-force attacks.

By incorporating these additional measures, you can further enhance the security of your Linux system. Remember, security is not a one-time setup but an ongoing process that requires regular attention and updates.

Conclusion

Securing your Linux system is an ongoing process that requires vigilance and proactive measures. By implementing the tips outlined in this article, you can significantly enhance your Linux security posture:

  1. Minimize software installation to reduce potential vulnerabilities.
  2. Keep your kernel and software up-to-date with the latest security patches.
  3. Use encrypted protocols like FTPS, SFTP, or OpenSSH instead of insecure ones.
  4. Isolate network instances to contain potential breaches.
  5. Employ security extensions to enforce additional limitations on programs.
  6. Implement strong password policies and maintain separate user accounts.
  7. Set up password aging to ensure regular password changes.
  8. Protect your personal information and monitor for potential data breaches.
  9. Use Kerberos for secure authentication in high-risk tasks.
  10. Configure comprehensive logging and auditing to track potential security threats.

Remember, cybersecurity is a constantly evolving field, and new threats emerge regularly. Stay informed about the latest security best practices and vulnerabilities specific to Linux systems. Regularly review and update your security measures to ensure your system remains protected against evolving threats.

By taking a proactive approach to Linux security, you can enjoy the flexibility and power of the operating system while minimizing the risk of successful attacks. Whether you’re a system administrator, a developer, or a casual Linux user, implementing these security measures will help safeguard your data and maintain the integrity of your system.

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