To elaborate, you sketch out the assembly you need, assemble it and literally drop those new bytes in.
Tools like IDA Pro, Binary Ninja, and Hopper make this quite easy. A good hex editor and knowing the file offsets is also fine. This is seen as magic because it is a bit of a lost art, but it turns out to be easy to learn.
Check out "crackmes" if anyone has become interested in this topic of mangling binaries by hand. They are fun and you will get results quickly on the easier challenges.
To elaborate, you sketch out the assembly you need, assemble it and literally drop those new bytes in.
Tools like IDA Pro, Binary Ninja, and Hopper make this quite easy. A good hex editor and knowing the file offsets is also fine. This is seen as magic because it is a bit of a lost art, but it turns out to be easy to learn.
Check out "crackmes" if anyone has become interested in this topic of mangling binaries by hand. They are fun and you will get results quickly on the easier challenges.
Also check out Microcorruption CTF.