smtp-penetration-testing SKILL.md skillA
smtp-penetration-testing from zebbern/claude-code-guide is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add zebbern/claude-code-guide/smtp-penetration-testing@v1.1Pins v1.1 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- zebbern/claude-code-guide
- Path
skills/smtp-penetration-testing/SKILL.md- Versions recorded
- 3
- Latest version
- v1.1, committed May 31, 2026
- First version recorded
- Jan 4, 2026
- Size
- 12,156 bytes
- Repository stars
- 4,700
- License
- MIT
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.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# 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 ```bash # 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 1. **SMTP Security Assessment Report** - Comprehensive vulnerability findings 2. **User Enumeration Results** - Valid email addresses discovered 3. **Relay Test Results** - Open relay status and exploitation potential …
Read the whole file at its exact version.
How to install
mdr add zebbern/claude-code-guide/smtp-penetration-testing@sha256:1f2a1ca7b95f91f0The line at the top of this page pins the label v1.1, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_zsqouzjulatyrwev)
5 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 3 versions of this file, between Jan 4, 2026 and May 31, 2026, about one every 74 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| v1.1 latest | 2026-05-31 | 164971d | 12,156 B | A | view · diff |
| v1.1 | 2026-01-20 | 27bf883 | 12,156 B | A | view · diff |
| git:20260104.9174e17 | 2026-01-04 | 9174e17 | 12,111 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (12156 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
zebbern/claude-code-guide · 4,700 stars · license MIT · pushed 2026-11-07 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_zsqouzjulatyrwev GET https://markdownregistry.com/api/v1/resolve?ref=zebbern/claude-code-guide/smtp-penetration-testing GET https://markdownregistry.com/api/v1/blob/1f2a1ca7b95f91f038f6fb654ac4c676b0263ac5c9a6cd11df4adb98324eb7f6
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.