ffuuuuunnyyy!! | Steganography

Problem Statement

Sometimes what you see doesn’t happen. 
Could you tell me what you see in this file?

Flag Format: BUBT{something}

ffuuunnnnyyyyy.png

Prerequisites

• <not sure what to put here>

Solution

Since the file is not opening normally, I started with strings and immediately found the flag at the bottom.

( for ss purpose, I added tail-n 3 to get the last three lines only )

Quite boring, right? How about we analyze the file a bit more?

• Starting with detecting the file type

  

  Found nothing useful :(

• Inspecting the magic headers

  

  

  hmm, 0D 0A 1A 0A are identical but the first few bytes aren’t. (I think they wiped it out 👀) Let’s try to fix it.

• Fixing magic bytes

  

  

• Previewing the repaired PNG (Nothing useful lol)

  Here’s the image we were given

  

Conclusion

It wasn’t much useful but I thought of introducing the magic bytes. I have solved various stegno problems and this method is one of the classic one (i.e repairing the magic headers to fix the file)

But remember during the contest, you have to submit the flag ASAP. It doesn’t matter how to retrieve it.

Credits

• Hashnode - for the amazing platform

• BUBT - for the workshop