Jpg Repair with Hexedit
- by Vince
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in Blog
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Hits: 6477
According to the description: "hexedit - view and edit files in hexadecimal or in ASCII". So how did I end up here? I was playing a ctf challenge and I came across a picture that was supposed to be a jpg file but was intentionally altered. Much Googling followed and after trying some fixit-type tools (that didn't work), I ended up on a post that talked about manually repairing the image file with hexedit.
We look at the man pages and it seems simple enough:
Hexedit FILENAME:
What we find that our jpg has been modified to look like a png file. For the manual repair, I came across several articles that weren't exactly clear but when I searched for jpg hex signature, I came across this Wiki page:
When we scroll down to jpg, we find:
We modify our file to match the Wiki example:
We hit F2 to save and then we're able to open the file:
Honestly, this kind of CTF is outside of my realm but I thought this was pretty cool because it's simple and yet I learned something new.