$500 isn't worth my time and I don't trust you'd pay up. But for anyone who wants to attempt to get him to pay up, here are three simple approaches:

(A1) In a POSIX constructor function in liblzma, set an alarm(2) for a few seconds later (once sshd has fully loaded).

(A2) In the alarm callback locate the original function that was patched using dlfcn, and mmap a page of modified code over the top that calls the exploit.

Or:

(B1) POSIX constructor function, call clone(2) to start a background thread.

(B2) In the background thread, sleep for a little, then patch the code as in A2 above.

Or:

(C1) POSIX constructor function that completely replaces the sshd process with a workalike that contains the exploit.

In A & B, for OSes (not Linux) that deny mmap, you'll need to find a struct or stack frame used by the function and work out how to adjust the data it uses or find a function pointer and exploit that.

It is weird to limit to "the same attack". Why does it even have to be the same attack? From the moment sshd loads your modified lib, you're literally running code with root privileges on the victim machine. You can literally run _any_ attack you wanted, with zero persistence. This is worse than a OpenSSH RCE.

Even in your own talk you basically admit this, so what are you doing here? If you think there's something here that everyone is missing but you don't, why not actually explain what it is?