Hex Editing - TechSecCTF/CTF-pwn-tips GitHub Wiki

Oftentimes you'll want to figure out how to edit a binary file. The "right" way to do this is with a good hex editor. (We recommend the 010 hex editor for which you can get a free 30 day trial).

If you're in a constrained environment and just want something quick and fast, a good approach is to use xxd, which is a command-line tool that outputs an easy-to-read hexdump. We can save the hexdump:

xxd binary_file > binary_file.xxd

and then edit it using whatever hex editor we prefer:

vim binary_file.xxd

and then recover our modified binary using the -r option:

xxd -r binary_file.xxd > new_binary_file