Digital Forensics: complete file header ----write up of 'rm03' for in Cyber FastTrack

Problem: find the flag in a file.

Tools: binwalk, ihex, file signature 

Solution:

Step 1: check the info of the file 

First I used 'binwalk' tool to check the file.

It looked like a hidden-message-picture because of 'Zlib'.

Step 2: Confirm the file type

I used ihex  to check the file, I found that it was ended by 'PNG'.

Step 3: find the file type

I check the header of the file with 'file signature' website. 

https://www.garykessler.net/library/file_sigs.html





Step 4: Complete the file header

It showed that it changed some bits in the header.So I changed  'AE42082' to '89504E47' and save the file.



 Then I added the extension of the file as 'png' then open it.
Flag: Are_Shoes_Hats_For_Feet








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