SMTP Penetration Testing

This README-style skill is a comprehensive, explicit active-testing guide for SMTP servers. It is not itself malware and contains no obfuscated or covert exfiltration logic, but it contains detailed, dual-use offensive techniques (user enumeration, relay exploitation, brute forcing) that pose significant operational risk if used without authorization. Recommend restricting distribution, adding mandatory authorization verification and safe-mode defaults (no external recipients, rate limits), guidance for secure storage/handling of captured credentials, and verifying provenance of recommended third-party tooling before installation.