How does one change an instruction with a hex editor?
assembly, hex, ida, instructions, reverse-engineering
Solution
If you've found a `jz`, it will either look like `74 XX` or `0F 84 XX XX XX XX`. If it's a `74`, change it to `75`. If it's the one with `84`, change it to `85`. This information can be found, among other places, in Intel's manual (volume 2A).
It will not vary between systems, as long as they're all x86 based, and if they aren't then `jz` and `jnz` may not even exist..
Problem
I am messing around with some reverse engineering, but I don't know how to change a jnz to jz with a hex editor. I understand it will vary between systems but I'm not sure where to look to find this information. I'm working on Mac OS X 64 bit and I disassembled code with IDA Pro.