This is a writeup about a retired HacktheBox machine: Ellingson This box is classified as a hard machine. The user is not too hard to get as it require to know python and password's cracking. The root part is really hard as this require the exploitation of a ROP buffer overflow.

Note: if you just want to play with the buffer overflow, the binary is available on this site, just go to the "Analysing the Buffer Overflow" section.