Hey and welcome to our new blog. Last week the team participated in the Cyber Grabs 0X03 Junior CTF which was a 12 Hours Jeopardy style team CTF

We managed to solve 21/29 challenges where we emerged 44/285 teams with 2750 points. In general, the challenges were fun despite a few challenges with the Infra.

OSINT

Misc

Reverse

Forensic

Mr Robot

Mr. Robot most famous TV show but least people know about it.

Solved by 05t3

We are presented with a .wav file and the first thing that comes to my mind is using Audacity & Sonic Visualizer to check if the flag is visible on the spectogram. Turns out that was a dead end. After sometime of research, i came across a tool on github that could get the flag, stegolsb. To install it, simply run:

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git clone https://github.com/ragibson/Steganography
cd Steganography
python3 setup.py install

stegolsb wavsteg -r -i sound_steg.wav -o output.txt -n 1 -b 1000

Breaking down the command above:

• WavSteg uses least significant bit steganography to hide a file in the samples of a .wav file.
• -r - is for recovering data from a sound file.
• -i - Path to a .wav file.
• -o - Path to an output file.
• -n - lsb-count (How many LSBs to use [default: 2])
• -b - How many bytes to recover from the sound file

For more information on stego-lsb, check out the official project description.

FLAG: CYBERGRABS{3VERY_8YTE_4RE_REAL_VALUE}

Web

Crypto