ctf-osint SKILL.md skillA

ctf-osint from cyr1s-dev/lynceus is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

Install it, pinned

mdr add cyr1s-dev/lynceus/ctf-osint@git:20260929.223300f

Pins git:20260929.223300f in mdr.lock. Pin the fingerprint instead.

Audit grade: A, 17 of 17 checks passed
Kind: SKILL.md skill
Repository: cyr1s-dev/lynceus
Path: resources/skills/ctf-osint/SKILL.md
Versions recorded: 1
Latest version: git:20260929.223300f, committed Sep 29, 2026
Size: 9,255 bytes
Repository stars: 11
License: AGPL-3.0

Provides open source intelligence techniques for CTF challenges. Use when gathering information from public sources, social media, geolocation, DNS records, username enumeration, reverse image search, Google dorking, Wayback Machine, Tor relays, FEC filings, or identifying unknown data like hashes and coordinates.

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

# CTF OSINT

Quick reference for OSINT CTF challenges. Each technique has a one-liner here; see supporting files for full details.

## Prerequisites

**Python packages (all platforms):**
```bash
pip install shodan Pillow
```

**Linux (apt):**
```bash
apt install whois dnsutils nmap libimage-exiftool-perl imagemagick curl
```

**macOS (Homebrew):**
```bash
brew install whois bind nmap exiftool imagemagick curl
```

## Additional Resources

- [social-media.md](social-media.md) - Twitter/X (user IDs, Snowflake timestamps, Nitter, memory.lol, Wayback CDX), Tumblr (blog checks, post JSON, avatars), BlueSky search + API, Unicode homoglyph steganography, Discord API, username OSINT (namechk, whatsmyname, Osint Industries), username metadata mining (postal codes), platform false positives, multi-platform chains, Strava fitness route OSINT
…

Read the whole file at its exact version.

How to install

The exact contents, by fingerprint

mdr add cyr1s-dev/lynceus/ctf-osint@sha256:a78f55e0162d3b09

The line at the top of this page pins the label git:20260929.223300f, 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.

Badge

[![mdr](https://markdownregistry.com/badge/art_2nhuxmlaaed7vakh.svg)](https://markdownregistry.com/a/art_2nhuxmlaaed7vakh)

4 badge image fetches in 30 days. What the badge shows.

Versions

The registry has recorded 1 version of this file, committed on Sep 29, 2026.

version	committed	commit	size	audit
git:20260929.223300f latest	2026-09-29	223300f	9,255 B	A	view

Audit of the latest version

A 17 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.

pass: Frontmatter block present
pass: Frontmatter declares a name
pass: Frontmatter declares a description
pass: Size between 200 bytes and 200 KB (9255 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

GitHub

cyr1s-dev/lynceus · 11 stars · license AGPL-3.0 · pushed 2026-09-29 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_2nhuxmlaaed7vakh
GET https://markdownregistry.com/api/v1/resolve?ref=cyr1s-dev/lynceus/ctf-osint
GET https://markdownregistry.com/api/v1/blob/a78f55e0162d3b09bc57456676ce0595d89a350b91e7496c1aedfaec458e21f9

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.