Aperi’CTF 2019 - Trip to space
Challenge details
| Event | Challenge | Category | Points | Solves |
|---|---|---|---|---|
| Aperi’CTF 2019 | Trip to space | Steganography | 50 | 38 |
Votre lecteur d’image vous ment-il ?
Challenge: Trip_to_space.zip - md5sum : a93693fb6f6ebc813510e60582e9d8d3
Methodology
Open it !
Open the image in a web browser or in a decent image viewer.
Gnome, Mobile, Windows… :
Web browser, MAC, … :
Explanation
Some image viewer implement gamma correction. This correction has a real impact on the image (here, the flag is displayed or not).
Fore more information about gamma correction and gamma steganography: - Gamma steganography - Gamma error in picture scaling
Flag
APRK{G4mm4-St3g4n0gr4phy}