Hacktoria runs OSINT and GEOINT challenges, many of them posted in its Discord. These are my writeups. Each one gives the answer near the top, then the method, including the hours lost on the wrong track.
Hacktoria GEOINT. Eighteen seconds of bog and spruce with nothing to read in the frame. The picture leads nowhere; the soundtrack is a 2008 xeno-canto recording, and its recordist logged the exact spot on observation.org.
Hacktoria GEOINT. A 2021 Street View frame with a black smoke plume over Flemish fields. Two wrong countries on the way, one search operator that mattered, and a press photo that pinned the house number.
Hacktoria GEOINT. One photo of a bp forecourt with the shop signs blurred out, and a question about when it was uploaded. A logo read through the blur, 211 candidate stations, and a delivery van that ruled out Google.
Hacktoria GEOINT. A blurred street photo, a courier van, a hot-sauce advert and a dark arch. The advert was a trap, Scotland was an hour wasted, and the answer was laminated on a wall the whole time.
An aerial shot of a KLM Cityhopper lifting off an unnamed runway. Runway markings give the scale, the scale gives the airport, and Denmark's open aerial imagery archive gives a timestamp accurate to the second — enough to name the exact flight and its arrival gate.
zsteg, Aletheia and five statistical detectors all called this file clean. The ZIP was sitting at offset 0 the whole time — hidden by splitting one bitstream across three different bitplanes.
Hacktoria GEOINT. No EXIF, no signs, no text. Here's how I got from an unmarked Scandinavian valley down to a single building — and the shortcut I ignored for six hours.
A GEOINT writeup: geolocating a censored Street View panorama in the Italian Alps using nothing but a poem's four constraints. Why the four black squares point at the poem, not at the picture.
A GEOINT writeup: locating a Colorado wildfire from an evacuation-zone map, and why the InciWeb URL will hand you the wrong incident number. With the WFIGS query that settles it.
A single blurry photo shot from a moving train. The deduction chain landed on the right country in the first thirty seconds — and then I talked myself out of it for three hours. A GEOINT writeup about tool-induced hallucination in data-sparse regions.