recon-fingerprint

recon-fingerprint is a skill for Claude Code, Codex from crazyMarky/pentest-skills. It costs 55 tokens per session (2,737 once invoked), scanned A, original, Apache-2.0.

A guide to identifying the technologies, web server details, content-delivery network, and web application firewall used by a website. It uses tools such as WhatWeb, wafw00f, HTTPX, and Nuclei.

In plain words
What is it for?
Use it to inspect HTTP headers, detect frameworks and services, identify a web application firewall, and run technology-focused scans on approved targets.
Why use it?
It helps establish what a web target is running before troubleshooting or conducting authorised security testing. The guide also highlights the need for written permission and a defined scope.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: reads .claude/ paths.

Good fit Use it to inspect HTTP headers, detect frameworks and services, identify a web application firewall, and run technology-focused scans on approved targets.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/crazymarky/pentest-skills/recon-fingerprint
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add crazyMarky/pentest-skills --skill recon-fingerprint
Clone the repo
git clone --depth 1 https://github.com/crazyMarky/pentest-skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for recon-fingerprint

README.md
[![agentmods](https://agentmods.dev/badge/skills/crazymarky/pentest-skills/recon-fingerprint/github.svg)](https://agentmods.dev/skills/crazymarky/pentest-skills/recon-fingerprint)
Your own site
<a href="https://agentmods.dev/skills/crazymarky/pentest-skills/recon-fingerprint"><img src="https://agentmods.dev/badge/skills/crazymarky/pentest-skills/recon-fingerprint/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for recon-fingerprint

Your own site · 80×15
<a href="https://agentmods.dev/skills/crazymarky/pentest-skills/recon-fingerprint"><img src="https://agentmods.dev/badge/skills/crazymarky/pentest-skills/recon-fingerprint.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,737 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high YARA Match · line 208
    YARA rule matched a hack tool or exploit indicator (offensive tools, reconnaissance, privilege escalation, or exploit frameworks).
    Fix: Remove offensive tool references and exploit code. Legitimate agent skills should not contain penetration testing tools, exploit frameworks, or reconnaissance utilities.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00055 $0.02737
Opus 5 $0.00028 $0.01368
Sonnet 5 $0.00011 $0.00547
Haiku 4.5 $0.00006 $0.00274

Measured 11d ago against content hash 1aa026d03801, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

recon-fingerprint scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 11d ago.

The scan reads SKILL.md. This mod also ships 4 executable files (scripts/extract_headers.py, scripts/fingerprint_storage.py, scripts/tech_matcher.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -I https://target.com
recon-fingerprint/SKILL.md · 399 lines

How it starts

The opening of the file, as written. The whole thing — 399 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Web Fingerprinting & WAF Detection

Authorization Warning

IMPORTANT: Web fingerprinting sends requests to target servers. Always ensure you have:

  • Written permission from the target application owner
  • Defined scope of authorized testing
  • Legal compliance with local regulations

Prerequisites

Required tools that must be installed on your system:

  • httpx - go install -v github.com/projectdiscovery/httpx/cmd/httpx@latest
  • nuclei - go install -v github.com/projectdiscovery/nuclei/v2/cmd/nuclei@latest

Optional tools:

  • wafw00f - pip install wafw00f
  • whatweb - Package manager installation
  • fingerprintx - go install github.com/praetorian-inc/fingerprintx/cmd/fingerprintx@latest

Quick Start

Most commonly used commands for web fingerprinting:

Basic Technology Detection

whatweb https://target.com

WAF Detection

wafw00f https://target.com

HTTP Header Analysis

curl -I https://target.com

Comprehensive Fingerprinting (Nuclei)

nuclei -u https://target.com -tags tech

Common Scenarios

Scenario 1: Quick Technology Fingerprinting

When you need to quickly identify the technology stack:

whatweb https://target.com --aggression 1

Parameters:

  • --aggression 1 - Quick scan (1-4, default 1)
  • -a 3 - More aggressive (more requests)
  • -v - Verbose output

Example:

whatweb https://target.com -a 3

Scenario 2: WAF Detection

When you need to detect WAF/CDN protection:

wafw00f https://target.com

Output shows:

  • WAF vendor (Cloudflare, AWS WAF, Imperva, etc.)
  • CDN in use
  • Firewall rules detected

Check multiple targets:

wafw00f -i targets.txt

Scenario 3: Server Header Analysis

When you need to analyze HTTP headers:

curl -I https://target.com

Detailed headers:

curl -v https://target.com 2>&1 | grep -i "< "

Common headers to check:

Server: nginx/1.18.0
X-Powered-By: PHP/7.4
X-AspNet-Version: 4.0.30319
X-Frame-Options: SAMEORIGIN
X-Content-Type-Options: nosniff
Strict-Transport-Security: max-age=31536000

Read the full file on GitHub · 399 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 11d ago First seen · 399 lines · 55 tokens per session scan A 1aa026d03801

Subscribe to this mod's changes

recon-fingerprint is a skill published in the GitHub repository crazyMarky/pentest-skills (308 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 55 tokens to every session and 2,737 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other skills, from other repositories

incident-response-fileanalyser

Static malware reverse-engineering and threat-intelligence triage for unknown files, Windows EXE/PE binaries, scripts, archives, ISOs, JavaScript, PowerShell, documents, and unpacked payloads. Use when a user provides a sample path, hash, filename, or file and asks whether it is malicious, benign, suspicious, contains…

crtvrffnrt/skills · 104 tokens

pentest-cve-vulnerability-research-helper

CVE and vulnerability research skill for exact CVE lookup, product/version applicability, exploit maturity, KEV/PoC status, source ranking, contradiction handling, and non-destructive validation guidance.

crtvrffnrt/skills · 49 tokens

pentest-hacktricks-finder

Support skill for HackTricks technique research, payload ideas, bypasses, prerequisites, caveats, and edge-case behavior across web, network, cloud, and application security topics. Use as owner only when research is the current blocker.

crtvrffnrt/skills · 56 tokens

pentest-web-enumeration

Authorized web enumeration for one or many websites or web applications, including live-target normalization, HTTP and TLS fingerprinting, technology and platform identification, virtual-host discovery, crawling, JavaScript and API endpoint extraction, focused directory and sensitive-file discovery, CMS-specific…

crtvrffnrt/skills · 101 tokens

web-pentest-skill

Analyze supplied artifacts from authorized web assessments with bounded defensive reasoning, evidence review, resumable workflow planning, and static reporting. Use for offline artifact analysis and explicitly reviewed task planning; never for autonomous exploitation, unreviewed target scanning, or executing…

crtvrffnrt/skills · 58 tokens

pentest-outbound-interaction-oob-detection

Outbound interaction and OOB validation for SSRF callbacks, blind XSS beacons, webhook abuse, XXE/OOB behavior, DNS/HTTP/HTTPS callback correlation, asynchronous server-side interaction proof, and egress validation.

crtvrffnrt/skills · 56 tokens