Suninatas Game 21

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50 words · 1 min
tags
#ctf#forensics#steganography#jpeg
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challenges

Game 21

We have a JPEG image to analyze. Check its properties:

Terminal window
❯ file monitor.jpg
monitor.jpg: JPEG image data, Exif standard: [TIFF image data, little-endian, direntries=11, description=SAMSUNG, ...], baseline, precision 8, 640x480, components 3

Check for embedded data with binwalk:

Terminal window
❯ binwalk monitor.jpg
Analyzed 1 file for 85 file signatures (187 magic patterns) in 9.0 milliseconds

Attempting to use stegseek reveals a structural issue:

Terminal window
❯ stegseek monitor.jpg
StegSeek 0.6
Invalid JPEG file structure: two SOI markers

The file contains multiple JPEG images (indicated by multiple Start of Image markers). Extract them using foremost:

Terminal window
❯ foremost monitor.jpg
❯ tree output/
output/
├── audit.txt
└── jpg
    ├── 00000000.jpg
    ├── 00000383.jpg
    ├── 00000765.jpg
    ├── 00001148.jpg
    ├── 00001532.jpg
    ├── 00001914.jpg
    ├── 00002297.jpg
    └── 00002681.jpg

Examine the extracted images to find the flag.

H4CC3R_IN_TH3_MIDD33_4TT4CK