A Complete Guide to Protecting a Linux Server From Hackers

A Complete Guide to Protecting a Linux Server From Hackers

Nearly 67.8% of public servers run on Linux and UNIX, such as Ubuntu, Fedora, Redhat, and CentOS. Linux is the go-to operating system for hackers, as the source code is free and easy to obtain. Since Linux is open-source, it is prone to hackers due to how easily they can modify or customize the system.

Linux security distros are also readily available, and these can be excellent substitute hacking tools. Therefore, Linux systems are often susceptible to viruses, malware, cookie theft, spoofing, spear phishing attack, social engineering, and DDoS attacks.

Thankfully, there are certain steps that you can take to keep your system completely safe from hackers. These are discussed in detail below.

Linux Overview

Linux is an open-source operating system that is very similar to Unix. It can support multiple users and multitasking. Mainframe computers, servers, PCs, smartphones, tablets, routers, embedded systems, and even most supercomputers use Linux.

A popular Linux system is the Linux Kernel which is an Android OS. Linux OS works similarly to Windows and Mac OS X. It can support numerous software and apps known as Linux distributions or distros.

Linux Hacking

Unfortunately, Linux systems are easy to hack due to the easily accessible source code and distros. Hobbyists or malicious actors can hack Linux:

Hobbyists are hackers that are searching for solutions to software issues. They want to expand the application of their software or hardware.

Malicious actors are thieves that try to exploit vulnerabilities in Linux software, apps, or networks. They attempt to gain unauthorized access to perform various illegal actions such as data theft and system modification.

Hacking Tools

Before we get into how you can protect your Linux system from hackers, knowing what hacking tools are generally used is essential. A deeper understanding will allow you to ward off hacking attempts:

• Intrusion detection software, password crackers, and scanning for network weaknesses are attempts made by malicious actors.
• Password cracking software helps hackers decode passwords and encrypted data.
• Some distros allow hackers to sniff Wi-Fi packets and detect network weaknesses.
• Databases, directories, and other important data can easily be tapped into using distros.
• Password theft distros are used in Linux Wi-Fi hacking.
• Network scanners create a virtual map of the network to show weaknesses, OS, firewall, and software information. They can also detect security holes in the Wi-Fi. Further information to enable distro hacking can also be obtained.
• Vulnerability scanning software helps steal passwords, enable denial of service attacks and detect configuration problems.

Protecting Linux From Hackers

Keep Your Linux System Updated

It will make it difficult for hackers to discover vulnerabilities in your Linux system if it is up to date. Statistics have shown that nearly 68% of hacking attempts were successful due to vulnerabilities in the system.

Keep applications and software updated to seal off any cracks hackers can use to get into your system. Set reminders and notifications to continually update your system whenever an update is available. Make sure to read the updated descriptions and fix patches. You can use cron to alert you regarding updates.

Enable Strong Network Security

A strong network can block out hackers. To enable strong network security, you can follow the steps below:

• Strengthen Linux Kernel network parameters by modifying /etc/sysctl.conf values
• Limit access to SSH TCP Wrappers by modifying /etc/hosts.allow to /etc/hosts.deny
• Use IPTables to establish a firm Firewall policy

Limit User Privileges By Modifying the File System

The file system allows privileges to every user. A strong file system will prevent malware attacks.

• Use Linux Chattr commands to restrict modification of core system binaries. This makes them immutable
• Enable limit access to /boot and root user
• User accessible directories such as /tmp, writable, and web folders should be mounted as NoExec
• Writable and webroot folders need to block new SetUID and SetGID files

Use a Strong Password and Login

Users are easy to attack, and hackers often use phishing and drive download attacks to steal login credentials.

• • All passwords should be a mix of numbers, alphabets, and symbols. They should also `3be at least 12 characters
  • Renew old passwords and prevent login after a certain amount of attempts
  • Enable IP-based restriction for SSH and databases

Scan for Malware

Since malware is the first step in hacking, malware detection tools can help block hacking attempts.

• Scan new files with antivirus software. Use FTP and Web Disk for scanning
• Use iNotify to enable scans for new files
• Use a Firewall and antivirus to monitor web traffic
• Use several antivirus signature databases to block malware

Harden Linux Kernel

It is important to harden the Linux Kernel to prevent hackers from exploiting vulnerabilities.

• ExecShield or Pax are excellent Kernel hardening patches
• Kernel hardening patches can protect Linux systems from name attacks, buffer overflows, and privilege escalation
• AppArmor or SELinux restrict users from taking irrelevant actions in regards to service. An example is restricting /etc access for developers

Use an Intrusion Detection System

Immediate action to block intrusion attempts can prevent unauthorized access and data breaches. To do this, you need to enable an intrusion detection system. This system will send out alerts and notifications in case of suspicious modification of logs and directories. You will also be notified if other unusual system behavior is detected.

• OSSEC is a sound intrusion detection system
• Processes from unknown locations, files, servers, or networks must be carefully monitored
• Enable monitoring of administrator-only files
• Monitor web traffic to detect malware and block its origins

Helpful Tips to Prevent Linux Hacking

• Use strong passwords and login credentials
• Create system backups regularly to prevent data loss in case an attack happens
• Use rootkit scanners to detect malware
• Disable automatic FTP uploads
• Disable IPv6 protocols
• Disable network ports that are not in use
• Keep the system, software and apps updated
• Disable root user login
• Change port 22 of SSH
• Uninstall irrelevant packages, modules, files, and apps
• Enable GnuPG encryption
• Enable strong Firewall and antivirus settings
• Make use of disk partitioning to store essential files in a different place
• All boot files should be set to read-only
• Use SFTP for secure data transfer and encryption
• cPHulk in WHM should be enabled
• Restrict guest FTP uploading

Endnote

We hope you found this article helpful and will be able to prevent hacking attempts made on your Linux operating system. Using a combination of all of the above will create a strong shield that most hackers will not be able to break.