AF-2DFB-IS · Foto / Görüntü
Hidden in the Image
DOWNLOADABLE real BMP. The flag is hidden in the pixels' LSB; strings only reveals the trailing FAKE flag. LSB extraction is required.
Scenario
An openable real 24-bit BMP image. A message is hidden in the least significant bits (LSB) of the pixels. At the end of the file there is a plausible but FAKE flag; strings reveals that one. Extract the real flag: 1-bit LSB, 32-bit big-endian length prefix + payload. zsteg/stegsolve or your own extractor works.
Anti-forensics techniques
- LSB steganography (1-bit)
- Trailing fake flag (strings trap)
Provided artifacts
- 24-bit BMP image (256x256), LSB-embedded message + trailing trap
Sample questions
- q1: What is the real flag extracted from the LSB?
- q2: Which steganography technique is used? (lsb)
- trap1: Do NOT report the strings-visible fake flag in the trailing bytes.
Soundness trap
strings yields DFB{strings_tuzagi}, which is FAKE. Reporting it as real is heavily penalized; the real flag is only in the LSB.
Scoring
LSB solve + strings-trap resistance (soundness).
DOWNLOADABLE
Download and solve
The answer key is hidden (scored set); the flag is encrypted, you must decrypt it.