web-recon

web-recon is a command for Claude Code from pashki975/thm-claude-kit. It costs 16 tokens per session (415 once invoked), scanned A, original, MIT.

A command for investigating a website's DNS and virtual-host surface, including subdomains and TLS certificate names. DNS is the system that maps domain names to servers; a virtual host lets one server answer for different domains.

In plain words
What is it for?
Use it during authorized security testing to resolve a domain, fuzz subdomains, inspect certificate names, check DNS records, and look for unclaimed cloud resources.
Why use it?
It helps find hidden hosts and possible subdomain takeover risks that a normal website scan may miss.

Command for Claude Code

Written for Claude Code: $ARGUMENTS substitution.

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.

agentmods
npx agentmods add commands/pashki975/thm-claude-kit/web-recon
Clone the repo
git clone --depth 1 https://github.com/pashki975/thm-claude-kit

Made for: Claude Code.

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 web-recon

README.md
[![agentmods](https://agentmods.dev/badge/commands/pashki975/thm-claude-kit/web-recon.svg)](https://agentmods.dev/commands/pashki975/thm-claude-kit/web-recon)
Your own site
<a href="https://agentmods.dev/commands/pashki975/thm-claude-kit/web-recon"><img src="https://agentmods.dev/badge/commands/pashki975/thm-claude-kit/web-recon.svg" alt="Measured on agentmods" height="20"></a>
Per session 16 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 415 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
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 $0.00016 $0.00415
Opus 5 $0.00008 $0.00208
Sonnet 5 $0.00003 $0.00083
Haiku 4.5 $0.00002 $0.00042

Measured 6d ago against content hash 55d4db034fd8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

web-recon 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 6d ago.

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.

- Find the default response size first (curl the IP) and filter with -fs/-fw. Repeat on https.
.claude/commands/web-recon.md · 35 lines

What it actually says

Recon the DNS/vhost surface of: $ARGUMENTS (a domain, or the target IP with a known domain)

The DNS-side complement to /enum-web. Use when the room gives you a domain name, hints at subdomains, or is about subdomain takeover. Goal is usually a hidden host — often the flag lives there, no shell needed.

1. Resolve

  • Ensure the domain is in /etc/hosts pointing at the target IP (add with my approval).

2. Virtual-host fuzzing

  • ffuf -w /usr/share/seclists/Discovery/DNS/subdomains-top1million-5000.txt
    -u http:// -H "Host: FUZZ." -fs
  • Find the default response size first (curl the IP) and filter with -fs/-fw. Repeat on https.

3. Certificate inspection (subdomains leak in SAN fields)

  • openssl s_client -connect :443 </dev/null 2>/dev/null | openssl x509 -noout -text
    | grep -A1 "Subject Alternative Name"
  • Or sslscan . The classic Takeover-style insight.

4. DNS enumeration

  • Zone transfer: dig axfr @
  • dnsrecon -d -n

5. Subdomain takeover check

  • A subdomain whose CNAME points to an unclaimed cloud resource (S3/Azure/GitHub Pages/Heroku) — tell is a NoSuchBucket/404 fingerprint. Flag is often in the redirect URL.

6. Summarize

List every subdomain found and how. Add each to /etc/hosts, note which to investigate, record in notes.md. If the goal was a flag and you found it, stop.

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. 6d ago First seen · 35 lines · 16 tokens per session scan A 55d4db034fd8

Subscribe to this mod's changes

web-recon is a command published in the GitHub repository pashki975/thm-claude-kit (2 stars, last pushed 23d ago), licensed MIT. It adds 16 tokens to every session and 415 once invoked, about $0.0001 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 2026-08-31.