Tags: forensics 

Rating: 4.0

In that challenge we provided by a png file.When we try to open that image we get an error.


Image Viewer already pointed out the error.But i wanna get more details about it for that i used the pngcheck tool.


And the tool gives the hex bytes in addition to that.So what is the CRC error?

<q>CRC (Cyclic Redundancy Check) is an error-detecting code commonly used in digital networks and storage devices to detect accidental changes to raw data.</q>,says Wikipedia.

This means there are changed bytes in my image.So i fired up hexeditor.

Searched the given bytes and replaced them with "01 AA E4 16" at between 0x0000001D and 0x00000020.


Original writeup (https://github.com/berkeakil/CTF-Writeups/blob/master/2018/RITSEC-18/Forensics/I%20am%20a%20Stegosaurus/README.MD).