Overview
SSH (Secure Shell) is the foundation of remote server administration, yet its default configuration leaves significant security gaps. A properly hardened SSH setup is not about security through obscurity—it’s about implementing defense-in-depth with modern cryptographic standards, strict authentication policies, and comprehensive monitoring.
Understanding the Threat Model
Before implementing security measures, it’s essential to understand what we’re protecting against:
- Brute-force attacks: Automated attempts to guess credentials
- Credential stuffing: Using leaked credentials from other breaches
- Man-in-the-middle attacks: Intercepting SSH connections
- Cryptographic weaknesses: Exploiting outdated algorithms
- Privilege escalation: Gaining unauthorized root access
- Session hijacking: Taking over active SSH sessions
Prerequisites
This guide assumes you have: