Ctf Osint

CTF OSINT

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

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
• [geolocation-and-media.md](geolocation-and-media.md) - Image analysis, reverse image search (including Baidu for China), Google Lens cropped region search, reflected/mirrored text reading, geolocation techniques (railroad signs, infrastructure maps, MGRS), Google Plus Codes, EXIF/metadata, hardware identification, newspaper archives, IP geolocation, Google Street View panorama matching, What3Words micro-landmark matching, Google Maps crowd-sourced photo verification, Overpass Turbo spatial queries
• [web-and-dns.md](web-and-dns.md) - Google dorking (including TBS image filters), Google Docs/Sheets enumeration, DNS recon (TXT, zone transfers), Wayback Machine, FEC research, Tor relay lookups, GitHub repository analysis, Telegram bot investigation, WHOIS investigation (reverse WHOIS, historical WHOIS, IP/ASN lookup)

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String Identification

• 40 hex chars -> SHA-1 (Tor fingerprint)
• 64 hex chars -> SHA-256
• 32 hex chars -> MD5

Twitter/X Account Tracking

• Persistent numeric User ID: https://x.com/i/user/ works even after renames.
• Snowflake timestamps: (id >> 22) + 1288834974657 = Unix ms.
• Wayback CDX, Nitter, memory.lol for historical data. See [social-media.md](social-media.md).

Tumblr Investigation

• Blog check: curl -sI for x-tumblr-user header. Avatar at /avatar/512. See [social-media.md](social-media.md).

Username OSINT

• whatsmyname.app (741+ sites), namechk.com. Watch for platform false positives. See [social-media.md](social-media.md).

Image Analysis & Reverse Image Search

• Google Lens (crop to region of interest), Google Images, TinEye, Yandex (faces). Check corners for visual stego. Twitter strips EXIF. See [geolocation-and-media.md](geolocation-and-media.md).
• Cropped region search: Isolate distinctive elements (shop signs, building facades) and search via Google Lens for better results than full-scene search. See [geolocation-and-media.md](geolocation-and-media.md).
• Reflected text: Flip mirrored/reflected text (water, glass) horizontally; search partial text with quoted strings. See [geolocation-and-media.md](geolocation-and-media.md).

Geolocation

• Railroad signs, infrastructure maps (OpenRailwayMap, OpenInfraMap), process of elimination. See [geolocation-and-media.md](geolocation-and-media.md).
• Street View panorama matching: Feature extraction + multi-metric image similarity ranking against candidate panoramas. Useful when challenge image is a crop of a Street View photo. See [geolocation-and-media.md](geolocation-and-media.md).
• Road sign OCR: Extract text from directional signs (town names, route numbers) to pinpoint road corridors. Driving side + sign style + script identify the country. See [geolocation-and-media.md](geolocation-and-media.md).
• Architecture + brand identification: Post-Soviet concrete = Russia/CIS; named businesses → search locations/branches → cross-reference with coastline/terrain. See [geolocation-and-media.md](geolocation-and-media.md).

MGRS Coordinates

• Grid format "4V FH 246 677" -> online converter -> lat/long -> Google Maps. See [geolocation-and-media.md](geolocation-and-media.md).

Google Plus Codes

• Format XXXX+XXX (chars: 23456789CFGHJMPQRVWX). Drop a pin on Google Maps → Plus Code appears in details. Free, no API key needed. See [geolocation-and-media.md](geolocation-and-media.md).

Metadata Extraction

exiftool image.jpg           # EXIF data
pdfinfo document.pdf         # PDF metadata
mediainfo video.mp4          # Video metadata

Google Dorking

site:example.com filetype:pdf
intitle:"index of" password

Image TBS filters: Append &tbs=itp:face to Google Image URLs to filter for faces only (strips logos/banners). See [web-and-dns.md](web-and-dns.md).

Google Docs/Sheets

• Try /export?format=csv, /pub, /gviz/tq?tqx=out:csv, /htmlview. See [web-and-dns.md](web-and-dns.md).

DNS Reconnaissance

dig -t txt subdomain.ctf.domain.com
dig axfr @ns.domain.com domain.com  # Zone transfer

Always check TXT, CNAME, MX for CTF domains. See [web-and-dns.md](web-and-dns.md).

Tor Relay Lookups

• https://metrics.torproject.org/rs.html#simple/ -- check family, sort by "first seen". See [web-and-dns.md](web-and-dns.md).

GitHub Repository Analysis

• Check issue comments, PR reviews, commit messages, wiki edits via gh api. See [web-and-dns.md](web-and-dns.md).

Telegram Bot Investigation

• Find bot references in browser history, interact via /start, answer verification questions. See [web-and-dns.md](web-and-dns.md).

FEC Political Donation Research

• FEC.gov for committee receipts; 501(c)(4) orgs obscure original funders. See [web-and-dns.md](web-and-dns.md).

IP Geolocation

curl "http://ip-api.com/json/103.150.68.150"

See [geolocation-and-media.md](geolocation-and-media.md).

Unicode Homoglyph Steganography

Pattern: Visually-identical Unicode characters from different blocks (Cyrillic, Greek, Math) encode binary data in social media posts. ASCII = 0, homoglyph = 1. Group bits into bytes for flag. See [social-media.md](social-media.md#unicode-homoglyph-steganography-on-bluesky-metactf-2026).

BlueSky Public API

No auth needed. Endpoints: public.api.bsky.app/xrpc/app.bsky.feed.searchPosts?q=..., app.bsky.actor.searchActors, app.bsky.feed.getAuthorFeed. Check all replies to official posts. See [social-media.md](social-media.md#unicode-homoglyph-steganography-on-bluesky-metactf-2026).

Resources

• Shodan - Internet-connected devices
• Censys - Certificate and host search
• VirusTotal - File/URL reputation
• WHOIS - Domain registration
• Wayback Machine - Historical snapshots

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: dailyyarn
• Source: dailyyarn/CTF-agent
• License: MIT

Install and usage instructions live in the source repository linked above.