Cuckoo with Microsoft Enhanced Mitigation Experience Toolkit (EMET)

I have been toying with the idea to retrieve Microsoft event log messages from my Cuckoo instances for a while. But I did not have any chance to make anything out of the idea, until now.

To get this to work, Cuckoo requires an extra auxiliary module for this purpose. Along with the Python WMI module installed on the guest, or at least I ended up using the WMI module, but you could easily use pywin32.

As you already have Python installed on the guest, you can use pip to install it.

Cuckoo runs any auxiliary module that is available in the directory:

cuckoo/analyzer/windows/modules/auxiliary

So this got me thinking (I know, crazy times!), as I have been doing some other work with EMET or rather logs from EMET. Why not combine the code above with EMET on the guest?

Obviously you need to install EMET (on the guest), do that and make sure it's active. Configure it after your specific needs. As your main goal might not be block, but to only catch EMET in action, you will need to configure EMET from the default blocking to audit mode. This will allow the malicious code to continue running even if it's detected by EMET.  

With the following lines of code, you will be able to retrieve what you need from the event log. Save the content in a file, in the above mentioned directory and you are good to go:

-------------------
import logging
import wmi
import sys

reload(sys)
sys.setdefaultencoding('utf-8')

from lib.common.abstracts import Auxiliary
from lib.common.results import NetlogFile

log = logging.getLogger(__name__)
dadada = []

class EMET(Auxiliary):

    def start(self):
        log.info("Starting EMET auxilary module")

    def stop(self):
        log.info("Collecting EMET events...")

        c = wmi.WMI(privileges=['Security'])
        for event in c._raw_query('SELECT * FROM Win32_NTLogEvent'):
            if event.SourceName == "EMET":
               #https://msdn.microsoft.com/en-us/library/aa394226(v=vs.85).aspx maybe add more values?
         dadada.append([event.SourceName, event.Category, event.Type, event.ComputerName, event.User, event.Message])

        bleekscheet = "\n".join(str(x) for x in dadada)
        nf = NetlogFile()
        nf.init("logs/emet_events.log")
        nf.send(bleekscheet)
        nf.close()
        return True
-----------------

Example of EMET events retrieved from the guest:

[u'EMET', 0, u'Error', u'<COMPUTERNAME>', None, u'EMET version 5.5.5871.31892\nEMET detected MemProt mitigation in iexplore.exe\r\n\r\nMemProt check failed:\n  Application \t: C:\\Program Files\\Internet Explorer\\iexplore.exe\n  User Name \t: <COMPUTERNAME>\\<USER>\n  Session ID \t: 1\n  PID \t\t: 0x474 (1140)\n  TID \t\t: 0x81C (2076)\n  API Name \t: kernel32.VirtualProtect\n  ReturnAddress \t: 0x0000000000446E60\n  CalledAddress \t: 0x000007FEFDA031E0\n  StackPtr \t: 0x00000000029AF4D0\n']

[u'EMET', 0, u'Error', u'<COMPUTERNAME>', None, u'EMET version 5.5.5871.31892\nEMET detected StackPivot mitigation in iexplore.exe\r\n\r\nStackPivot check failed:\n  Application \t: C:\\Program Files\\Internet Explorer\\iexplore.exe\n  User Name \t: <COMPUTERNAME>\\<USER>\n  Session ID \t: 1\n  PID \t\t: 0x71C (1820)\n  TID \t\t: 0x46C (1132)\n  API name \t: kernel32.WinExec\n  ReturnAddress \t: 0x000000007775C8FF\n  CalledAddress \t: 0x00000000775B8D80\n  Thread stack area range: [0x3172000..0x3180000]\n  StackPtr \t: 0x000000000543FB30\n']

Please note that the coding style is not officially approved by @skier_t =)(but I'm as always very grateful for his help!) Hopefully there will be a better way of doing this in the future, natively in Cuckoo.

/Mikael

Defeating WMI detection of VirtualBox take 2

My previous attempt to twart WMI detection of VirtualBox, by disabling the Plug and Play service, had the mildly obnoxious side effect of disallowing the OS to check if it was registered or not.

This resulted in that, already registered installations became unlicensed (The same issue applied to MS Office installations)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\PlugPlay

Being that It is always hard to find time for fun/interesting research. I had to put this issue back into my ToDo list, until now. And I guess leaving a problem to fend for itself for a while makes you look at it in a more logical way then you previously did, at least this was true for this issue at this time.

So enters my second attempt to solve this issue.

The remaining culprit that enables one to detect the presence of VirtualBox through WMI(1) is the






As we have chosen not install VirtualBox Guest Additions, the device is missing it's driver (Error 28, I will come back to this one later). It is that device that is detected, DEV_CAFE. (If you need a quick fix goto 2.) 

My first thought was to ty to replace corresponding values in the registry, but that one did not work out either.

Microsoft Windows does not supply you with a command line option to install/remove/uninstall devices by default. They have however an application that is available in their Windows Driver Kit (WDK), called DevCon. 

DevCon sounded like the way to go, given the fact that I had to use a none pre-installed application anyway.

But once again, reality came repelling down the ceiling and smacked me in the head. DevCon was not able to remove a device that was not fully installed, remember the Error 28.

DevManView from Nirsoft(3) to the rescue! While DevCon was not able to remove the device, DevManView were!

So now that we have a working solution that we can script, it was time to figure out how to make it user friendly given that we have to use a 3rd party application.

The easiest way would have been to leave the "user" to move the application to the VM guest themselves... but why miss the opportunity to do something hideous?

So I decided to embed the binary in the batch script by Base64 encode DevManView.exe. The Base64 encoded part is then in the guest decoded, up on execution of the batch script.

I guess I could try to sugar coat this by pointing to the fact that it is a bit more user friendly..

Please remember to pick the version of DevManView corresponding to the guests O architecture.

An updated version of the script can be found at: https://github.com/nsmfoo/antivmdetection/

As always any kind of feedback is welcomed

/Mikael

(1) If you use previous versions of the antivmdetction script

(2) just right-click on the Base System Device and choose uninstall ;)

(3) http://www.nirsoft.net/utils/device_manager_view.html