Comment by toast0
10 hours ago
This isn't that hard (that's not to say this is easy, it is tricky). Your executable should be a statically linked stub loader with an awful lot of data, the stub loader dynamically links your real executable (and libraries, including libc) from the data and runs it.
To add to this, in case of any remaining confusion. You can implement your own execve in userspace. [0] But the kernel's execve is a piece of machinery that invokes the loader so obviously it follows that you're free to make any changes you'd like to the overall process.
Bonus points if you add compression or encryption and manage to trip a virus scanner or three. [1]
[0] https://grugq.github.io/docs/ul_exec.txt
[1] https://blackhat.com/presentations/bh-usa-07/Yason/Whitepape...