Course
Gralhix OSINT Exercises
Sofia Santos
Thirty-two free exercises, mostly geolocation and image analysis, each with a full walkthrough. The best free practice set for visual OSINT.
Sofia Santos publishes numbered OSINT exercises on her site: a photo or a scenario, one to four tasks, and difficulty ratings given separately for novices and experts. Every exercise has a published walkthrough, hers or a starred community one, so you can check your reasoning rather than just your answer.
Worth it if
- You want to practise geolocation and chronolocation without waiting for a CTF
- You learn from comparing your reasoning to a worked solution
- You are preparing for Trace Labs, Quiztime, or a Bellingcat workshop
- You need safe material: images are used for education, not real-case targets
Skip it if
- You want people-search, breach, or infrastructure practice; the set is mostly visual
- You need a certificate or a syllabus to show someone
What is inside
- 01
Geolocation exercises
Place a photo or video from visible clues, from street-level scenes to landscapes. The first exercise, geolocating a tweeted photo, is rated hard for beginners and medium for experts.
- 02
Chronolocation
Work out when something was taken from shadows, weather, signage, and imagery history.
- 03
Image and social pivots
Follow an image back to its source, or an account across platforms, with the reasoning written out.
- 04
Walkthroughs
Author videos or write-ups for every exercise, plus community solutions marked as recommended.
What you will be able to do
- Work through a geolocation methodically: clues, hypotheses, confirmation
- Estimate when a photo was taken from environmental evidence
- Recognise where your own reasoning went wrong by comparing it to a worked solution
How current it is
New exercises arrive a few times a year; the newest is from 2025 and community write-ups continued into 2026. Because the exercises use fixed images and published solutions, they do not age the way tool tutorials do.
- Updated
- 32 exercises; latest added in 2025
- Maintained
- Actively maintained
How to get the most from it
- 01
Write your reasoning before you read the walkthrough
Two paragraphs: what you noticed, what you concluded, and how sure you were. Then compare. The gap is the lesson.
- 02
Start at your rated level
Use the novice ratings to pick easy ones first. The first exercise is harder than it looks.
- 03
Time yourself on the second pass
Redo an exercise a month later under a clock. Speed on familiar problems is what CTFs reward.
Strengths
- Every exercise has a solution you can learn from
- Written by a working geolocation analyst
- Safe to practise on, with no real subjects
Limitations
- Narrow by design: mostly imagery
- No feedback beyond the walkthroughs
- Additions are infrequent
Pair it with
FAQ
Questions, answered
Are the answers public?
Yes. Every exercise page links to a full walkthrough, which is the point: you learn from the method, not from getting the flag.
Can I use these for a class or a team?
They are free to use for learning. The images belong to third parties and are posted for educational use only, so do not republish them.
Learned the method? Practise it on real data
The resources above teach the craft. When you want to run real lookups across breach, people, domain, and crypto sources without opening a dozen vendor accounts, that is what SearchIn is for.
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- Credits never expire
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