Top 10 ways to secure your Linux server

In this blog post, we will discuss the importance of securing your Linux server and provide step-by-step instructions on how to do so. From keeping your system and software up to date, to using a firewall and strong passwords, we will cover all the essential measures you need to take to protect your server from unauthorized access and attacks. Additionally, we will provide an example of how to set up a firewall and secure SSH access on an Ubuntu 20.04 LTS server. Don’t miss this essential guide on securing your Linux server and keeping your data safe. Whether you’re a system administrator or a developer, this post will give you the tools and knowledge you need to secure your Linux server and protect sensitive information.

Securing a Linux server is an important task for any system administrator. A secure server not only protects sensitive data and personal information, but it also helps prevent unauthorized access and attacks. Here are some steps you can take to secure your Linux server:

1. Keep your system and software up to date. Running the latest software versions ensures that you have the latest security patches and fixes. You can use the package manager of your distribution (apt, yum, dnf, etc) to check for updates and install them.
2. Use a firewall. A firewall is a software or hardware component that controls access to your server. You can use iptables, which is a built-in firewall in Linux, to block or allow traffic based on specific rules.
3. Use strong passwords. Strong passwords are essential to protecting your server from brute force attacks. Use a mix of letters, numbers, and special characters, and avoid using common words or phrases.
4. Limit access to your server. Only allow the necessary users and applications to access your server, and restrict access to specific IP addresses if possible. Use SSH keys for remote logins instead of passwords.
5. Monitor your server for suspicious activity. Use tools like logwatch or syslog-ng to monitor system logs for suspicious activity, such as failed login attempts or unauthorized access.
6. Use a VPN. A Virtual Private Network (VPN) encrypts all the data that is sent between your server and the client, which makes it much harder for someone to intercept and read that data.
7. Regularly backup your data. Regularly backing up your data ensures that you can restore your server to a known good state in case of an attack or failure.

Top 10 ways to secure your Linux server?

1. Update your system and software:

Update your system and software: This command updates the package lists and upgrades any installed packages to their latest versions. This is important because it ensures that you have the latest security patches and fixes.

sudo apt-get update && sudo apt-get upgrade

2. Install and configure a firewall:

Install and configure a firewall: This command installs the Uncomplicated Firewall (ufw) package and allows incoming SSH connections. The firewall is then enabled, which helps to block unauthorized access and attacks.

sudo apt-get install ufw
sudo ufw allow ssh
sudo ufw enable

3. Change the default SSH port:

Change the default SSH port: This command opens the SSH configuration file and changes the default port number. This makes it harder for attackers to guess which port to attack, as they typically target the default port.

sudo nano /etc/ssh/sshd_config

4. Disable root login over SSH:

Disable root login over SSH: This command opens the SSH configuration file and disables root login over SSH. This makes it more difficult for attackers to gain access to your server as the root user.

sudo nano /etc/ssh/sshd_config

5. Use SSH keys for authentication:

Use SSH keys for authentication: This command generates an SSH key pair, which can be used for authentication instead of a password. SSH keys are more secure than passwords, as they are not susceptible to brute-force attacks.

ssh-keygen

6. Use Fail2Ban to protect against brute force attacks:

Use Fail2Ban to protect against brute force attacks: This command installs Fail2Ban, which is a tool that monitors system logs for repeated failed login attempts and temporarily bans the IP addresses that are causing them.

sudo apt-get install fail2ban

7. Use AppArmor or SELinux to add an additional layer of security:

Use AppArmor or SELinux to add an additional layer of security: This command installs AppArmor, which is a Linux Security Module (LSM) that provides a way to restrict what programs can do. This helps to prevent unauthorized access and attacks.

sudo apt-get install apparmor-utils
sudo aa-enforce /etc/apparmor.d/usr.sbin.mysqld

8. Use chkrootkit to check for rootkits:

Use chkrootkit to check for rootkits: This command installs chkrootkit, which is a tool that checks for signs of a rootkit on the system. Rootkits are malicious software that can hide the presence of an attacker on a system.

sudo apt-get install chkrootkit
sudo chkrootkit

9. Use rkhunter to check for malware:

Use rkhunter to check for malware: This command installs rkhunter, which is a tool that checks for signs of malware on the system. Malware can be used to gain unauthorized access to a system and cause damage.

sudo apt-get install rkhunter
sudo rkhunter --check

10. Keep an eye on your logs:

Keep an eye on your logs: This command shows the last few lines of the auth.log file, which contains information about system logins and other authentication-related events. Monitoring this log can help you detect suspicious activity and take action to protect your server.

sudo tail -f /var/log/auth.log

In conclusion, securing a Linux server is crucial for protecting sensitive data and personal information, as well as preventing unauthorized access and attacks. By following the steps outlined in this blog post, including keeping your system and software up to date, using a firewall, strong passwords, limiting access, monitoring for suspicious activity, using a VPN and regularly backing up your data, you can ensure the security of your Linux server. Additionally, the provided example of how to set up a firewall and secure SSH access on an Ubuntu 20.04 LTS server serves as a practical guide for securing your server. Remember that security is an ongoing process, so make sure to regularly review and update your security measures. This blog post has provided essential information and guidance for anyone looking to secure their Linux server and protect sensitive information.