Cut Short

Challenge Text

This image refuses to open in anything, which is a bit odd. Open it for the flag!

Challenge Work

First, we look at the image presented to us:

PhillipJFryIV ractf/cut_short » file flag.png
flag.png: data

We notice its is not recognizable. Let us open both this file and a valid .png with a hex editor, like HexFiend.

Doing so we can see that 00000000 49454E44 AE426082 is at the end of the valid file, but is right after the PNG magic bytes (89 50 4E 47 0D 0A 1A 0A) at the start of this file. Cutting 00000000 49454E44 AE426082 from its current location and appending it to the end of the file allows us to open the new .png file and read our flag.

ractf{1m4ge_t4mp3r1ng_ftw}