[Th3B4h0z]

let's discuss HTB - KHP Protocol

[x1rx]

anyone solved this ? any hints ?

[nitwitse]

anyone solved this ? any hints ?

Bit late to the party, but some hints for anyone still looking... this challenge is a heap overflow exploit.

I'd recommend installing pwndbg extension to gdb to run the server process and inspect the heap.

From pwndbg / gdb you can then e.g. run these commands:

p (char*[10])IN_MEM_KEYS
p (char*)KEYS_BUF

... in order to see where on the heap things are being created when malloc() and free() do their thing.

Don't forget: malloc() is quite deterministic in re-using bins that have been freed().

[LOOOP]

Any hint i am stuck!!