# Level 00 ## how to login username: level00 password: level00 ## Goal run `getflag` as user `flag00` ## Actually doing something When logging in, nothing to see ```sh level00@SnowCrash:~$ ls -la . total 12 dr-xr-x---+ 1 level00 level00 100 Mar 5 2016 . d--x--x--x 1 root users 340 Aug 30 2015 .. -r-xr-x---+ 1 level00 level00 220 Apr 3 2012 .bash_logout -r-xr-x---+ 1 level00 level00 3518 Aug 30 2015 .bashrc -r-xr-x---+ 1 level00 level00 675 Apr 3 2012 .profile ``` Trying to find anything to do: ```sh level00@SnowCrash:~$ find / -user flag00 -print 2>/dev/null /usr/sbin/john /rofs/usr/sbin/john ``` The `/rofs` seems to be a read only version of the root (`/`), meaning that we dont really care about it running `file` on `/usr/sbin/john` says that it is an ASCII file lets open it ```bash level00@SnowCrash:~$ cat /usr/sbin/john cdiiddwpgswtgt ``` lets also confirm that the `/usr/sbin/john` and `/rofs/usr/sbin/john` is the same ```bash level00@SnowCrash:~$ sha256sum /rofs/usr/sbin/john /usr/sbin/john c36e744787ff060c5711ac4b5d06439a9f265169fb82946a8d1052f4a935103e /rofs/usr/sbin/john c36e744787ff060c5711ac4b5d06439a9f265169fb82946a8d1052f4a935103e /usr/sbin/john ``` They are indeed the same. I have fiddled with the iso itself, and it uses a readonly filesytem to store everything, so this seems to be how they still have some kind of "normal" system We now have something that looks like it wants us poke at it (the text). The file itself isn't executable (even if it is in `/usr/sbin/`) Cyberchef is a nice tool to fiddle with random ciffers, so lets have fun :D link: [https://cyberchef.org/](https://cyberchef.org/) After having fun with the website, we can see that with a ROT11 (also named Caesar substitution), we find some english text: ``` nottoohardhere ``` is it the password of the user `flag00` ? ```bash level00@SnowCrash:~$ su flag00 Password: Don't forget to launch getflag ! flag00@SnowCrash:~$ getflag Check flag.Here is your token : x24ti5gi3x0ol2eh4esiuxias ``` yes it is !