On: Can I exec a new process without an executable fil...

[tedunangst]

One could also exec any available 64 bit program and then overwrite all its memory with ptrace on Linux.

[ohwutwathere → tedunangst]

Correct but in lots of scenarios (containers etc) you cannot execute ptrace() but you can execute mmap(), mprotect(), read(), write() which is all you really need. Edit: and fork().

See something I published just a month ago: https://github.com/anvilsecure/ulexecve/