From 91245a4da1f52f5bdf3cc580ceb7bc69fa7e395d Mon Sep 17 00:00:00 2001 From: poorvi1910 <146640913+poorvi1910@users.noreply.github.com> Date: Tue, 20 Feb 2024 22:51:31 +0530 Subject: [PATCH] Create README.md --- .../forensics/Covert Communications/README.md | 22 +++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 BITSCTF-2024/forensics/Covert Communications/README.md diff --git a/BITSCTF-2024/forensics/Covert Communications/README.md b/BITSCTF-2024/forensics/Covert Communications/README.md new file mode 100644 index 0000000..747be77 --- /dev/null +++ b/BITSCTF-2024/forensics/Covert Communications/README.md @@ -0,0 +1,22 @@ +### CHALLENGE: +rskbansal hacked into nasa mainframe and intercepted a radio signal from deep space along with a very SUS image. +He tried using data representation but soon realised that he seems to be missing something...Help him figure out the secret!!! +HINT: skbansal asked Huffman for help, he suggested to maybe try messing around with histograms. + +### SOLVE: +The challenge description mentions 'deep space' which hints at using DeepSound for analyzing the wav file.
+On putting the secret.wav in DeepSound, we get a secret.zip file

+![image](https://github.com/poorvi1910/Cryptonite/assets/146640913/87e55eca-613e-419f-91f2-03892ca8effa) + +The zip file required a password to unzip.
+On using sstv on the wav file, we obtain the password of the zip file as 'mogambro'

+On entering the password, the zip file gave two pkl files: enc_data.pkl and temp.pkl
+The hint mentioned Huffman and histograms. Searching steganography techniques using Huffman and histograms I came across the below GitHub repo:
+ +https://github.com/TejveerSingh13/Image-Steganography
+ +The link contains a README file which has a youtube link along with written instructions as to how to use the attached python files that contain the actual working code for the Huffman Encoding and Compression algorithm.
+ +On using the enc_data.pkl file along with the decode option in the histo-shift.py code, we get a text file with a bunch of binary numbers. Now this text file and the tempo.pkl file need to be used in the huffman.py code which gives another text file that contains the decoded flag. + +**FLAG: bitsctf{s73g4n06r4phy_15_n07_45_345y_45_17_533m5}**