Train your reverse engineering skills with OverTheWire Leviathan, using radare2 for binary disassembly to extract passwords from compiled programs.

Walkthrough

Level 0 - ls and cat 

ssh -p 2223 [email protected]
# leviathan0 http://overthewire.org/wargames/leviathan/leviathan0.html

$ ls -a
.  ..  .backup  .bash_logout  .bashrc  .profile
$ ls .backup
bookmarks.html
$ grep pass .backup/bookmarks.html
This will be fixed later, the password for leviathan1 is rioGegei8m

Level 1 - radare2 bin disassembly

ssh -p 2223 [email protected]
# rioGegei8m http://overthewire.org/wargames/leviathan/leviathan1.html

$ ls
check
$ check
password: test
Wrong password, Good Bye ...
$ radare2 check
[0x08048440]> aa
[0x08048440]> pdf @ main
|           0x0804854d      c745f0736578.  mov dword [local_10h], 0x786573 ; 'sex' # store 'sex' in variable local_10h
|           0x08048587      e844feffff     call sym.imp.getchar        ; int getchar(void)
|           0x0804858c      8845f4         mov byte [local_ch], al # store user input in variable local_ch
|           0x080485a6      8d45f0         lea eax, [local_10h] # push local_10h as arg1
|           0x080485aa      8d45f4         lea eax, [local_ch] # push local_ch as arg2
|           0x080485ae      e8fdfdffff     call sym.imp.strcmp # call strcmp(arg1, arg2)
# so the password must be 'sex', let's try
[0x08048440]> !./check
password: sex
$ id
uid=12002(leviathan2) gid=12001(leviathan1) groups=12001(leviathan1)
$ cat /etc/leviathan_pass/leviathan2
ougahZi8Ta

Level 2 -

ssh -p 2223 [email protected]
# ougahZi8Ta http://overthewire.org/wargames/leviathan/leviathan2.html

Going further