OSINT
Open-Source Intelligence challenges require you to find information about targets using only publicly available data: social media, image metadata, domain records, satellite imagery, and public databases.
OSINT (Open-Source Intelligence) is the collection and analysis of information from publicly available sources — websites, social media, public records, satellite imagery, domain registrations, job postings, and more.
It is used by law enforcement, journalists, penetration testers, and threat intelligence analysts to build profiles of individuals, organisations, and infrastructure without any direct interaction with the target.
In a CTF, OSINT challenges give you a starting point (a username, a photo, a company name, a tweet) and ask you to discover a specific fact — a real-world location, an email address, a date, or a connection between entities. No hacking tools are needed; only research skills and patience.
Common workflow: identify all data points in the brief → reverse image search → check social media profiles → inspect WHOIS / Shodan / Certificate Transparency logs → cross-reference findings → geolocate if needed.
Sample Challenge
- Crop the embedded image from the screenshot. Reverse-image search with Google, TinEye, and Yandex — Yandex finds a match on a local tourism blog.
- The blog post names the city district. Cross-reference with Google Street View to identify the visible building facade and street signage.
- Check the Wayback Machine for the original tweet URL (extracted from the screenshot URL bar) — the archived version still has the original image with GPS EXIF intact.
- Run
exiftool original.jpg— GPS coordinates appear. Convert DMS to decimal and look up in Google Maps. - The pin drops on a specific cafe. The street address is the flag.