Server Administration

You are reading Part 33 of the 57-part series: Harden and Secure Linux Servers. [Level 4] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Regular vulnerability scans help identify and remediate security flaws before attackers exploit them. These scans: ✅ Detect outdated software, misconfigurations, and security weaknesses. ✅ Help ensure compli…

You are reading Part 32 of the 57-part series: Harden and Secure Linux Servers. [Level 4] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Two-Factor Authentication (2FA) adds an extra layer of security to SSH logins, requiring a second verification step (such as a push notification, SMS code, or phone call) before granting access. This signifi…

You are reading Part 31 of the 57-part series: Harden and Secure Linux Servers. [Level 4] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Application sandboxing isolates applications from the rest of the system, preventing them from accessing sensitive files, making unauthorized system modifications, or exploiting vulnerabilities. This enhance…

You are reading Part 30 of the 57-part series: Harden and Secure Linux Servers. [Level 3] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. A Web Application Firewall (WAF) acts as a protective shield between users and your web application, filtering and blocking malicious traffic before it reaches your server. This is essential for preventing: …

You are reading Part 29 of the 57-part series: Harden and Secure Linux Servers. [Level 3] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Configuration drift occurs when system settings, security policies, or application configurations deviate from their intended secure baseline. These deviations can lead to: ✅ Security vulnerabilities – Unint…

You are reading Part 28 of the 57-part series: Harden and Secure Linux Servers. [Level 3] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. The Principle of Least Privilege (PoLP) ensures that users, processes, and applications only have the minimum level of access necessary to perform their tasks. This helps: ✅ Prevent accidental or intentional…

You are reading Part 27 of the 57-part series: Harden and Secure Linux Servers. [Level 3] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Regularly rotating encryption keys, passwords, and certificates reduces the risk of old, compromised credentials being used for unauthorized access. Attackers often exploit stolen or leaked credentials, so p…

You are reading Part 26 of the 57-part series: Harden and Secure Linux Servers. [Level 3] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. A Host-Based Intrusion Detection System (HIDS) continuously monitors system logs, file integrity, user activity, and network behavior to detect suspicious activity. If an attacker compromises your server, HI…

You are reading Part 25 of the 57-part series: Harden and Secure Linux Servers. [Level 3] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. The Domain Name System (DNS) translates domain names (e.g., example.com) into IP addresses. However, standard DNS is not secure, and attackers can manipulate DNS records to redirect users to malicious sites …

You are reading Part 24 of the 57-part series: Harden and Secure Linux Servers. [Level 3] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Encryption ensures that even if attackers gain access to your data, they cannot read or modify it without the correct decryption key. This is crucial for: ✅ Protecting sensitive files from unauthorized acces…

You are reading Part 23 of the 57-part series: Harden and Secure Linux Servers. [Level 3] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Rate limiting protects your Linux server from denial-of-service (DoS) attacks and brute-force login attempts by restricting the number of requests or connections an IP address can make within a certain perio…

You are reading Part 22 of the 57-part series: Harden and Secure Linux Servers. [Level 3] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. File Integrity Monitoring (FIM) ensures the security and integrity of critical system files by detecting unauthorized modifications. Attackers often modify configuration files, binaries, or logs to hide thei…

You are reading Part 21 of the 57-part series: Harden and Secure Linux Servers. [Level 3] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Each open port on a server represents a potential entry point for attackers. If unnecessary ports are left open, they can be scanned, exploited, or used for unauthorized access. By limiting open ports to onl…

You are reading Part 20 of the 57-part series: Harden and Secure Linux Servers. [Level 2] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Port knocking is a security technique that hides your SSH port from attackers. Instead of leaving SSH (port 22) open, the server keeps it closed by default. Only users who send a specific sequence of connect…

You are reading Part 19 of the 57-part series: Harden and Secure Linux Servers. [Level 2] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. AppArmor (Ubuntu/Debian) and SELinux (CentOS/RHEL) are Mandatory Access Control (MAC) systems that enforce strict security policies on processes and services. Unlike traditional Linux permissions, these syst…

You are reading Part 18 of the 57-part series: Harden and Secure Linux Servers. [Level 2] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. The sudo command grants elevated privileges, allowing users to execute system-critical commands. If an unauthorized or compromised user gains sudo access, they can modify system files, install malware, or es…

You are reading Part 17 of the 57-part series: Harden and Secure Linux Servers. [Level 2] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Network segmentation enhances security by isolating critical services and limiting unnecessary communication between different parts of your infrastructure. If an attacker gains access to one system, segment…

You are reading Part 16 of the 57-part series: Harden and Secure Linux Servers. [Level 2] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. 1. Install Google Authenticator on Your Linux Server:sudo apt install libpam-google-authenticator -y # Debian/Ubuntu sudo yum install google-authenticator -y # CentOS/RHEL2. Configure MFA for Your …

You are reading Part 15 of the 57-part series: Harden and Secure Linux Servers. [Level 2] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Install ClamAV (Antivirus for Linux): sudo apt install clamav -y # Debian/Ubuntu sudo yum install clamav -y # CentOS/RHELUpdate the ClamAV virus database: sudo freshclam (Ensures the latest virus definit…

You are reading Part 14 of the 57-part series: Harden and Secure Linux Servers. [Level 2] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Install Lynis (a powerful Linux security auditing tool): sudo apt install lynis -y # For Debian/Ubuntu sudo yum install lynis -y # For CentOS/RHELRun a system security audit: sudo lynis audit system Review…

You are reading Part 13 of the 57-part series: Harden and Secure Linux Servers. [Level 2] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. Resource limits prevent system abuse by restricting how many processes a user can run at once. Without limits, a malicious user or process could spawn excessive tasks, leading to denial-of-service (DoS) atta…

You are reading Part 12 of the 57-part series: Harden and Secure Linux Servers. [Level 2] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. 1. Use rsync for File Backupsrsync is a powerful tool that syncs files and directories between locations. Backup to a local directory: rsync -av --delete /important_data /backup_location -a → Preserves file …

You are reading Part 11 of the 57-part series: Harden and Secure Linux Servers. [Level 2] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. The Linux kernel is responsible for managing system operations, including network communication and security policies. Attackers often exploit weak kernel settings to perform DDoS attacks, IP spoofing, and o…

You are reading Part 10 of the 57-part series: Harden and Secure Linux Servers. [Level 1] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. The SSH service (Secure Shell) is a critical entry point for remote server management, but leaving default settings unchanged makes it vulnerable to brute-force attacks, unauthorized access, and exploits. Co…

You are reading Part 9 of the 57-part series: Harden and Secure Linux Servers. [Level 1] This series covers progressive security measures, from fundamental hardening techniques to enterprise-grade defense strategies. Each article delves into a specific security practice, explaining its importance and providing step-by-step guidance for implementation. To explore more security best practices, visit the main guide for a full breakdown of all levels and recommendations. System logs are essential for tracking activities, detecting security incidents, and troubleshooting issues. Without proper logging, it’s difficult to identify unauthorized access, configuration changes, or p…