Milkman: Creating Processes as Any Currently Logged in User

One of the problems with using PSEXEC from Metasploit (any of the psexec modules) is that it runs as SYSTEM. What’s the problem with that? Isn’t SYSTEM god mode? Ya, and normally I’d agree that it’s the best level to have, but the defenses these days have gotten better, and getting direct connections out is pretty rare. That leaves proxies, and as you know SYSTEM doesn’t get any proxy settings.

Here is a blog post that I made about setting the proxies for SYSTEM but leaving settings like this set is not only sloppy but hard to clean up.

Along comes RunAsCurrentUser-2.0.3.1.exe I found this gem by messing up a search on google for RunAsUser. Found it on this IBM support post.

Link to direct download:
http://software.bigfix.com/download/bes/util/RunAsCurrentUser-2.0.3.1.exe

Here is a mirror uploaded to my Post Exploitation repo:
https://github.com/mubix/post-exploitation/blob/master/win32bins/RunAsCurrentUser-2.0.3.1.exe

This binary takes a path to another executable as an argument. It then finds the currently logged in user and starts the provided executable as that user. AWESOME! This basically solves the whole PSEXEC->SYSTEM no-proxy settings issue. And it’s created by a legitimate company for legitimate reasons? w00tw00t. Game on!

Only two problems:

1. It is 335K, which doesn’t seem like much but over high latency lines that can take an eternity to transfer, especially over doubly encrypted channels like with a reverse_https meterpreter session.
2. It takes an argument which normally isn’t a huge challenge, but in our specific use case, psexec modules in Metasploit, it isn’t something we can do easily. You would have to upload your C2 binary, as well as the 335K RunAsCurrentUser over to the target host, then run the psexec_command module to execute them both, one as the argument of the other. Kinda sloppy.

So I set to try and figure out how this binary did it’s magic. As I’m not much of a reverse engineer I uploaded it to VirusTotal so I could take a look at it’s insides (plus, double check to see if it was being detected as malicious at all).

As far as I can tell the important pieces are the Windows API calls ImpersonateLoggedOnUser, and CreateProcessAsUserA. I set to trying to reproduce what it did in AutoIT (awesome stuff if you have never checked it out). I couldn’t quite get the API calls right, so I decided to give C++ a shot. Turned out to be pretty simple. I present to you “Milkman”:

https://gist.github.com/mubix/5d0cacdabfe092922fa3 (full source included below)

This program (once compiled) takes one argument (or none at all) and runs calc.exe for every instance of the process you tell it to. If you run it without arguments it auto selects explorer.exe. So if you create a service:

C:\temp\>sc create SuperService binpath= C:\Temp\milkman.exe type= own start= auto
[SC] CreateService SUCCESS

It will start up every time the computer starts, which is completely useless, since there won’t be any users logged in at that point, but you get where this can go. Features to add to this at point are:

1. Create a service binary that responds to START/STOP/PAUSE commands and such so that running this as a persistence method would actually be useful.
2. Add a loop so that it continues to run checking for explorer.exe every so often so it can catch when someone is logged in.
3. Finally the obvious one is to change it from being calc.exe that it runs by accepting another argument or some other kind of config option.

Thoughts? What would you like Milkman to do, or what use case do you think a tweak would make it work better for? Leave a comment below.

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The Internets Own Boy

Anyone who knows me knows that I live in a tiny world of offensive security, so much so that I miss large world events entirely. (Like elections and hurricanes)

I didn’t know Aaron Swartz, or even 1% of what he was doing in the world to make it a better place and for that I am ashamed. I will do better, to look around, see what needs to be changed in this world and make it a reality.

The following is a Documentary about the life of Aaron Swartz. If you live under a similar rock as I, you can start here: http://en.wikipedia.org/wiki/Aaron_Swartz

Watch, learn, share, and help continue a legacy that Aaron started.

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Why Good Leaders Make You Feel Safe

This talk really touched home with me and I wanted to share it, and not just because he talked about Marines. ;–)

Forward this talk on to your fellow employees, boss, etc.

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Go Home InfoSec, You're Drunk

Let me start off by saying this post is easy for me to write in one facet as I’ve never been a heavy drinker or much enjoyed the taste of alcohol. So if you need a reason to disregard what I say next, I leave the door open.

I am still pretty much a runt in the infosec community as I didn’t even begin learning computers (outside of playing games on them) until 2005. However, one thing that has nagged at me for a long time is the intertwined nature of hacking/infosec and drinking. Its almost a right of passage in the common fraternity style. The problem lies in the fact that you don’t really “graduate” and leave those parties behind.

Now, I have certainly partaken in my share of parties and consumption, even with that nagging feeling in the back of my head. It didn’t really take root until just recently. I was at a conference where a student (who was not 21) that looked very much like an older version of my oldest child said that he was going to skip dinner to go get wasted with XYZ “Infosec Rockstar”.

That scared me into thinking that if my son goes into Infosec he will be basically expected to drink like an alcoholic. How can I want my kid to be expected (not forced) to drink a shot on stage if he gets accepted to speak at DEF CON.

We (the infosec community) are few, and we lose too many to idiotic things like drug overdose, drinking and driving, and other stupidly preventable crap. For that reason I actually don’t want to share the thing I feel so passionate about with my own kids.

My call to action is this:

If you are a conference goer, try going one con completely dry, and if you already do, maybe ask friend to join you.

If you are speaker, enough of the drinks on stage and drinking games. Do you really want the next generation, those you are trying to teach, to remember that part of your talk instead of the rest?

If you are a conference organizer, maybe a completely dry day at the con? or an AA meeting space?

If you are a podcaster, if you drink during the cast, make it about the taste and selection, instead of how wasted and totally useless the next hour of your listeners life will be.

ShmooCon runs an AA meeting at the con

Lets stop losing our friends and family because we are too weak to say ‘no thank you’ when someone approaches the dais with a shot.

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Installing PyCrypto on OSX Mavericks

Keeping it here for notes and just in case anyone else runs into this same issue.

brew install pip
sudo ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future pip install pycrypto

If you have a better way please leave a comment below!

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Effective NTLM / SMB Relaying

SMB Relay has been around for a long while. I even have a post about using it along with LNK files here: MS08-068 + MS10-046 = Fun until 2018

Here is the problem though. Most of the tools to exploit it either catch the authentication in NTLMv2/NTLMv1 (which is not always easy to crack) or assume administrative access (because they attempt to PSEXEC with the incoming session). Well, since MS08-068 thats much harder to pin down. You have to know who is going to hit your relay server and what other location they might be an admin on. You also have to a service you want to run on that target.
Current Tools:

• SMBRelay
• SMBRelay3
• SpiderLabs Responder
• SMBRelayX in Impacket
• HTTP NTLM Relay Metasploit Module
• SMB Relay PSExec Metasploit Module
• Oracle SMB Relay Metasploit Module
• SAP SMB Relay Metasploit Module

“Soft” relay tools:

Now, some would argue that you just spin up the relay at a target then leave it until one pops. I’m not really a fan of that. You will not only be creating multiple access attempt log entries, but you are also just throwing away all of those user authentication attempts. There are 3 tools that agree with me.

Squirtle

Squirtle is awesome plus it’s written in a language I understand (ruby) but it has one serious downfall, many of the post-auth features are left up to the user to develop. It does have a great API but needs some coding to get to do certain things.

Intercepter-NG

I have tested Intercepter-NG out a lot and it has some fantastic features, not to mention that it does relaying on a Windows host, which is impressive all by itself (due to 445 default bind). My only problem with it is that it’s closed source. But definitely recommended.

Zack Attack

The 3rd is a tool called “ZackAttack” by Zack Fasel, you can find it here on Github:ZackAttack. You can find the video of the talk releasing this tool on Youtube. So what is so special about this tool? Other than the fact that most of the web interface is broken horribly it has this amazing bit of code that acts as a SOCKS proxy. This SOCKS proxy identifies SMB or HTTP traffic that has NTLM authentication going on and rewrites it based on captured sessions.

What does this mean? If I use SpiderLab’s Responder, for instance, to spoof/get/fake a bunch of users into connecting to my machine via automatic or forced methods to the capture/keep services that ZackAttack spins up, I can then run smbclient or Outlook or Web browser, push it through the ZackAttack SOCKS proxy, pick a username out of the captured names, and use any password I want when asked, and the SOCKS proxy will automatically replace it en route with the valid session information.

This way I can use every authentication that comes in to its highest potential for pwnage. The video below shows how this can be used to connect to a “Network share”

Update: One thing to mention that ZackAttack does that I haven’t seen other tools do, even Squirtle or Intercepter-NG is getting 3+ successful authentications out of a single relay from a user. ZackAttack does this with some clever HTTP Keep-Alive and SMB “reauth” kung fu.

Other References:

• 2014-02 SpiderLabs – Responder 2.0 Owning Windows Networks Part 3
• 2014-01 NetSPI Blog – SMB Attacks Through Directory Traversal
• 2013-06 Ares – SMB Hijacking Kerberos is defeated
• 2013-04 SANS Pentesting Blog – SMB Relay Demystified and NTLMv2 Pwnage with Python
• 2013-01 Core Security Training Video – How To Perform a SMB Relay Attack
• 2013-01 Mark Gamache – NTLM Challenge Response is 100% Broken
• 2012-12 NetSPI Blog – Executing SMB Relay Attacks via SQL Server using Metasploit
• 2012-07 WebstersProdigy – Metasploit Generic NTLM Relay Module
• 2012-04 Ares – Actuality of SMBRelay in Modern Windows Networks
• 2011-01 Digital Security Research Group Blog – SMBRelay Bible
• 2009-07 Carnal0wnage – Metasploit Oracle TNSCMD SMBRelay Demo
• 2008-11 Ron Bowes – Preventing SMB Relay Attacks
• 2008-08 Kurt Grutzmacher at DEF CON 16 – NTLM is Dead!
• 2008-06 John Heasman – Stealing Password Hashes with Java and IE
• 2008-04 Eric Rachner: NTLM Relay Attacks – Released tool ‘scurvy’
• 2007-08 HD Moore and Valsmith – Tactical Exploitation
• 2004-12 (ARCHIVE.ORG) Jesse Burns at SySCAN – NTLM Authentication Unsafe
• 2002-01 Azbil SecurityFriday Ltd – ScoopLM
• 2001-03 @lantaCon – Reference from March 31 2001 talk

I tried finding all the original/semi original references about SMB (LM/NTLM) Relaying. If you have others please leave a comment below so I can add them to the list.

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CCDC Red Teamer's Creed

This is my box. There are many like it, but they are all mine.

My malware is my best friend. It is my life. I must master it as I must master my life.

My malware, without me, is useless. Without my malware, I am useless. I must drop my malware true. I must rootkit better than my enemy who is trying to kill my binary. I must kit him before he kits me. I will…

My malware and I know that what counts in this war is not the boxes we pop, the noise of our root dance, nor the cheers coming from the Red Team room. We know that it is the root that count. We will root…

My malware is human, even as I, because it is my life. Thus, I will learn it as a brother. I will learn its weaknesses, its strength, its parts, its extensions, its dlls and its exes. I will keep my malware av free and ready, even as I am ready. We will become part of each other. We will…

Before God, I swear this creed. My malware and I are the defenders of my botnet. We are the masters of our enemy. We are the saviors of my shells.

So be it, until victory is the Red Team’s and there is no enemy, but peace!

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