SmashTheStack.org – BlackBox – Level 1

SmashTheStack.org – BlackBox – Level 1

Objective:

Get the pass for level 2

Solution:

So this is the first level for smashthestack.org blackbox. You are given the user/pass for level one and need to get the level 2 pass

So first things first let’s ssh

putty.exe -ssh level1@blackbox.smashthestack.org 2225
 Using username "level1".
level1@blackbox.smashthestack.org's password:

lets start with ls to see where we landed and what there

level1@blackbox:~$ ls -al
total 24
drwxr-x---  2 root   level1 4096 Oct 23  2016 .
drwxr-xr-x 17 root   root   4096 Mar 22  2012 ..
lrwxrwxrwx  1 root   root      9 Sep 13  2016 .bash_history -> /dev/null
-rw-r--r--  1 level1 gamers   35 Sep  3  2016 .bashrc
-rw-------  1 root   gamers 1170 Oct 23  2016 .viminfo
-rwxr-xr-x  1 level2 level1 7591 Apr 22  2017 login2
 

Cool There is a file called login2 that we have access to lets see what kind of file it is

level1@blackbox:~$ file login2
login2: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.4.1, dynamically linked (uses shared libs), for GNU/Linux 2.4.1, not stripped

is a binary file so lets see what it does

level1@blackbox:~$ ./login2
Access Code: jjfjf
Access Denied!
 

It prompts for an access code then presumably it gives us the level 2 password if we have the right code

Let’s see what lives inside with xxd

level1@blackbox:~$ xxd login2  - I’ve edited the output down to the relevant bits
00005c0: c390 9090 5589 e553 83ec 04e8 0000 0000  ....U..S........
00005d0: 5b81 c32c 1100 00e8 24fe ffff 595b c9c3  [..,....$...Y[..
00005e0: 0300 0000 0100 0200 5061 7373 466f 7232  ........PassFor2

00005f0: 0041 6363 6573 7320 436f 6465 3a20 002f  .Access Code: ./
0000600: 6269 6e2f 7368 0041 6363 6573 7320 4465  bin/sh.Access De
0000610: 6e69 6564 2100 0000 0000 0000 ffff ffff  nied!...........

Looks like we might have the password there

PassFor2

Lets see what happens if we give that as the access code

level1@blackbox:~$ ./login2
Access Code: PassFor2
sh-3.1$
 

no error and the bash changed

I wonder if that is the password for Level 2

Lets try it

 putty.exe -ssh level2@blackbox.smashthestack.org 2225
 Using username "level2".
level2@blackbox.smashthestack.org's password:
Last login: Wed Oct 16 18:20:27 2019 from 68.15.179.18
level2@blackbox:~$

Cool we got that one