Good box, interesting! Few hints from me:
- For initial exploitation - enumerate articles/source of the page(s?)!
- For user - do some basic research of what kind of file is that in user directory, then use the linux command which should tell what kind of file is that or what it should be - all answers will be in output of that basic linux command.
- For root - don’t bother diving too deep. Everything is in front of you, just learn by what binary the config (!) file can be ran and you will get an answer.
You may want to understand how all that is working - then write one-liner bash script to check difference of running processes from previously running processes every second. I used a diff command to compare two variables… You may need to run it for several minutes to get the more accurate answer - For root shell - use what you learned for getting root.txt, read more files, modify (yeah you can not only read, but to write as well with that simple tool) one critical file and you will get your sweet root shell