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CYBERDUDEBIVASH Linux Security Hardening Checklist (2026)

The Ultimate Enterprise Blueprint for Securing Linux Servers, Workloads, Containers, and Cloud Environments

Author: CyberDudeBivash Threat Research Division
Website: https://www.cyberdudebivash.com

TLDR

This is the official 2026 CyberDudeBivash Linux Security Hardening Checklist — a battle-tested, enterprise-grade hardening framework used across global organizations. It is designed to secure Linux servers, cloud workloads, containers, SSH access, kernel parameters, file integrity, privilege escalation paths, and zero-trust network boundaries. This checklist aligns with modern threat models including RCE exploits, misconfigurations, supply-chain attacks, and IAM misuse.

Why Linux Hardening Matters in 2026

Linux powers 90% of enterprise cloud workloads, web servers, containers, DevOps pipelines, databases, and backend APIs. With the rise of ransomware gangs, nation-state intrusions, supply-chain compromises, and AI-powered automated exploits, modern Linux systems face continuous attacks.

The CyberDudeBivash Security Lab has identified four major threat categories for 2026:

Misconfigured SSH and remote access
Privilege escalation vulnerabilities
Container escape and kernel abuse
Zero-day exploitation in Linux packages and libraries

The CyberDudeBivash Hardening Checklist addresses these in a structured enterprise format.

1. SSH & Remote Access Hardening

Disable Password Authentication

PasswordAuthentication no

Enforce SSH Key Authentication

Store keys in ~/.ssh/authorized_keys with proper permissions.

Disable Root Login

PermitRootLogin no

Change Default SSH Port

Reduces automated botnet attacks.

Enable Fail2Ban

Protects SSH from brute-force attacks.

Use Two-Factor Authentication (U2F, TOTP)

2. User & Privilege Management

Use Least Privilege Everywhere

No user should have sudo unless required.

Use Sudo Logs & Restrictions

Defaults logfile="/var/log/sudo.log"

Enforce Password Aging Policies

Use chage to enforce expiration and rotation.

Monitor New User Creations

Unexpected accounts = compromise indicator.

3. File System & Permission Hardening

Secure /tmp and /var/tmp

/tmp  nodev,nosuid,noexec

Remove World-Writable Permissions

Deploy Immutable Bit for Critical Binaries

chattr +i /sbin/init

Enable File Integrity Monitoring (FIM)

Use Wazuh or OSSEC for enterprise monitoring.

4. Network Hardening

Enable Firewall (UFW / Firewalld)

Disable Unused Services

systemctl disable bluetooth.service

Block All Except Required Ports

SSH
HTTP/HTTPS
Database ports (if internal only)

Enable Reverse Path Filtering

Prevents spoofing attacks.

5. Kernel & Sysctl Hardening

Enable SYN Flood Protection

net.ipv4.tcp_syncookies = 1

Disable IP Forwarding

net.ipv4.ip_forward = 0

Disable Kernel Pointer Exposure

kernel.kptr_restrict = 2

Enable Kernel Lockdown Mode

Prevents rootkits & kernel tampering.

6. Logging, Monitoring & Threat Detection

Enable Auditd

Logs critical system calls and privilege misuse.

Enable Sysmon for Linux

Enterprise-level event visibility.

Deploy Wazuh or Elastic Agent

Monitor:

New privileged users
Privilege escalation attempts
Changes to sudoers
Unauthorized processes
Reverse shells & malware

7. Application Hardening

Enable SELinux or AppArmor

Use Seccomp Profiles for Services

Disable Unnecessary PHP, Python, Java Versions

Scan Servers for CVEs Weekly

OpenSCAP
Lynis
Nessus
OpenVAS

8. Cloud Linux Hardening (AWS / Azure / GCP)

Use Instance Metadata Version 2 (IMDSv2)

Prevents SSRF-based credential theft.

Enforce IAM Roles instead of Keys

Disable Public IPs for Linux VMs

Use Cloud Firewall (NSG, Security Groups)

Enable Cloud Logs:

AWS: CloudTrail, GuardDuty
Azure: Defender for Cloud
GCP: Chronicle, Security Command Center

9. Container & Kubernetes Hardening

Do Not Run Containers as Root

Enable Kubernetes Pod Security Standards (PSS)

Use CIS Benchmarks

Enable Runtime Protection:

Falco
Sysdig
Wazuh

Scan Container Images

Trivy
Anchore
Clair

10. Linux Incident Response Checklist

Collect system logs: /var/log/secure, /var/log/auth.log
Dump running processes
Check for binaries with SUID bit
Scan for rootkits using rkhunter, chkrootkit
Dump network connections using ss -tulpn
Take memory snapshot for forensics

Download CyberDudeBivash Security Tools

Strengthen Linux security with our enterprise-grade tools:

CyberDudeBivash Open Port Checker Pro
CyberDudeBivash Wazuh Ransomware Rule Pack
Cephalus Hunter — Session Hijack Detector
CyberDudeBivash DFIR Toolkit

Download: https://www.cyberdudebivash.com/apps-products

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