Friday, November 8, 2013

Yet Another SMB PSEXEC (Y.A.S.P) Tool

I was working on my own version of an updated standalone PSEXEC tool in ruby, leveraging the MSF standalone as a base along with some of the newer modules that have been released. Unfortunately SMBEXEC 2.0 was recently released which pretty much does the same thing functionality wise but has threading so its probably a bit cooler but thought I would still post mine out there for anyone who cares to take it for a spin. It is single target focused and a little different in the look and feel in comparison to some of the others available so who knows. It works for me, hope it works for someone else too....

I first started off trying to do things on my own by writing classes to wrap the smbclient tool which now supports the pass-the-hash option or can be fairly easily patched to address this. This Samba suite also includes the rpcclient tool which I originally planned to leverage to make some magic happen. Well I got the wrappers working, but was not able to get things fully working with just these two classes. I do recommend playing around with rpcclient as it is an interesting tool and can lead to a lot of insight against a remote target but that's another story. So after giving up on the rpcclient option i did some checking on the net and found some great references from Mubix and Chris Gates on the MSF standalone tool and some ways to play with it. As Chris and Rob point out the librex library is available outside of MSF as a standalone gem which gives you tons of power to do all kinds of neat things on your own. Being that the hard work was already done and available as reference in MSF i decided to borrow what i could from there and merge with my own wrappers and code to get what I wanted. The end result is an smbclient with all the psexec fun and then some.

It can do some basic recon without creds, which I am working on improving but its main focus is on re-using valid credentials. Once authenticated it's capable of running single commands using the PSEXEC technique or jumping into a pseudo shell to execute multiple commands.

Download registry hives for offline pillaging

Leverage MSFVENOM to generate shellcode and then run payloads using PowerShell (my favorite):

NOTE: You need to specify the hostname for Vista+ targets or connection will fail. You can use raw netbios requests or tool like nbtscan to find this pretty quickly and without any pain. On older targets you can omit this field for connection configuration.

The full list of available options once authenticated:

And here are a few demo videos I made to show off how you can use it....

Y.A.S.P. vs Standalone 2k3 Server:

Y.A.S.P. + PowerShell Payload vs Windows 7:
NOTE: It does leverage MSFVENOM currently to generate shellcode which gets converted over to PowerShell acceptable format and then executed via PowerShell command

Y.A.S.P. vs 2k3 Domain Controller + Active Directory Dumping 101:

You can find all the source code along with all the tools used or referenced in the above videos on my github page here: SOURCE + TOOLS

You can keep an eye on Github as I will be working on this one over time to smooth out a few things and add a few more things to it which I wasn't comfortable with rolling out just yet but again just sharing to share and inspire more coders to code cool shit. Until next time, Enjoy!