Smtp Penetration Testing
Should be used when the user asks to "perform SMTP penetration testing", "enumerate...
Install
npx skills add zebbern/claude-code-guide --skill smtp-penetration-testing -g -a claude-code -y- Repository
- zebbern/claude-code-guide4.7k
- Category
- Testing
- Updated
- 4d ago
- License
- MIT
- Context cost
- Mediumabout 2,937 tokens
- Runs scripts
- No, instructions only
What it does
This skill should be used when the user asks to "perform SMTP penetration testing", "enumerate email users", "test for open mail relays", "grab SMTP banners", "brute force email credentials", or "assess mail server security". It provides comprehensive techniques for testing SMTP server security.
SMTP Penetration Testing
Purpose
Conduct comprehensive security assessments of SMTP (Simple Mail Transfer Protocol) servers to identify vulnerabilities including open relays, user enumeration, weak authentication, and misconfiguration. This skill covers banner grabbing, user enumeration techniques, relay testing, brute force attacks, and security hardening recommendations.
Prerequisites
Required Tools
# Nmap with SMTP scripts
sudo apt-get install nmap
# Netcat
sudo apt-get install netcat
# Hydra for brute force
sudo apt-get install hydra
# SMTP user enumeration tool
sudo apt-get install smtp-user-enum
# Metasploit Framework
msfconsole
Required Knowledge
- SMTP protocol fundamentals
- Email architecture (MTA, MDA, MUA)
- DNS and MX records
- Network protocols
Required Access
- Target SMTP server IP/hostname
- Written authorization for testing
- Wordlists for enumeration and brute force
Outputs and Deliverables
- SMTP Security Assessment Report - Comprehensive vulnerability findings
- User Enumeration Results - Valid email addresses discovered
- Relay Test Results - Open relay status and exploitation potential
- Remediation Recommendations - Security hardening guidance
Core Workflow
Phase 1: SMTP Architecture Understanding
Components: MTA (transfer) → MDA (delivery) → MUA (client)
Ports: 25 (SMTP), 465 (SMTPS), 587 (submission), 2525 (alternative)
Workflow: Sender MUA → Sender MTA → DNS/MX → Recipient MTA → MDA → Recipient MUA
Phase 2: SMTP Service Discovery
Identify SMTP servers and versions:
# Discover SMTP ports
nmap -p 25,465,587,2525 -sV TARGET_IP
# Aggressive service detection
nmap -sV -sC -p 25 TARGET_IP
# SMTP-specific scripts
nmap --script=smtp-* -p 25 TARGET_IP
# Discover MX records for domain
dig MX target.com
nslookup -type=mx target.com
host -t mx target.com
Phase 3: Banner Grabbing
Retrieve SMTP server information:
