Allow COM object registration in a Windows Defender Application Control policy

Applies to:

  • Windows 10
  • Windows 11
  • Windows Server 2016 and later

Note

Some capabilities of Windows Defender Application Control are only available on specific Windows versions. Learn more about the Application Control feature availability.

The Microsoft Component Object Model (COM) is a platform-independent, distributed, object-oriented system for creating binary software components that can interact. COM specifies an object model and programming requirements that enable COM objects to interact with other objects.

Important

Some information relates to pre-released product which may be substantially modified before it's commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

COM object configurability in WDAC policy

Prior to the Windows 10 1903 update, Windows Defender Application Control (WDAC) enforced a built-in allow list for COM object registration. While this mechanism works for most common application usage scenarios, customers have provided feedback that there are cases where additional COM objects need to be allowed. The 1903 update to Windows 10 introduces the ability to specify allowed COM objects via their GUID in the WDAC policy.

Note

To add this functionality to other versions of Windows 10, you can install the following or later updates.

Get COM object GUID

Get GUID of application to allow in one of the following ways:

  • Finding a block event in Event Viewer (Application and Service Logs > Microsoft > Windows > AppLocker > MSI and Script), and extracting GUID
  • Creating an audit policy (using New-CIPolicy –Audit), potentially with a specific provider, and use the info from the block events to get the GUID

Author policy setting to allow or deny COM object GUID

Three elements:

  • Provider: platform on which code is running (values are Powershell, WSH, IE, VBA, MSI, or a wildcard “AllHostIds”)
  • Key: GUID for the program you wish to run, in the format Key="{33333333-4444-4444-1616-161616161616}"
  • ValueName: needs to be set to "EnterpriseDefinedClsId"

One attribute:

  • Value: needs to be “true” for allow and “false” for deny

    Note

    Deny only works in base policies, not supplemental policies

  • The setting needs to be placed in the order of ASCII values (first by Provider, then Key, then ValueName)

Examples

Example 1: Allows registration of all COM object GUIDs in any provider

<Setting Provider="AllHostIds" Key="AllKeys" ValueName="EnterpriseDefinedClsId">
  <Value>
    <Boolean>true</Boolean>
  </Value>
</Setting>

Example 2: Blocks a specific COM object from being registered via Internet Explorer (IE)

<Setting Provider="IE" Key="{00000000-4444-4444-1616-161616161616}" ValueName="EnterpriseDefinedClsId">
  <Value>
    <Boolean>false</Boolean>
  </Value>
</Setting>

Example 3: Allows a specific COM object to register in PowerShell

<Setting Provider="PowerShell" Key="{33333333-4444-4444-1616-161616161616}" ValueName="EnterpriseDefinedClsId">
  <Value>
    <Boolean>true</Boolean>
  </Value>
</Setting>

How to configure settings for the CLSIDs

Here's an example of an error in the Event Viewer (Application and Service Logs > Microsoft > Windows > AppLocker > MSI and Script):

Log Name: Microsoft-Windows-AppLocker/MSI and Script
Source: Microsoft-Windows-AppLocker
Date: 11/11/2020 1:18:11 PM
Event ID: 8036
Task Category: None
Level: Error
Keywords:
User: S-1-5-21-3340858017-3068726007-3466559902-3647
Computer: contoso.com
Description: {f8d253d9-89a4-4daa-87b6-1168369f0b21} was prevented from running due to Config CI policy.

Event XML:

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-AppLocker" Guid="{cbda4dbf-8d5d-4f69-9578-be14aa540d22}" />
    <EventID>8036</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x4000000000000000</Keywords>
    <TimeCreated SystemTime="2020-11-11T13:18:11.4029179Z" />
    <EventRecordID>819347</EventRecordID>
    <Correlation ActivityID="{61e3e871-adb0-0047-c9cc-e761b0add601}" />
    <Execution ProcessID="21060" ThreadID="23324" />
    <Channel>Microsoft-Windows-AppLocker/MSI and Script</Channel>
    <Computer>contoso.com</Computer>
    <Security UserID="S-1-5-21-3340858017-3068726007-3466559902-3647" />
  </System>
  <EventData>
    <Data Name="IsApproved">false</Data>
    <Data Name="CLSID">{f8d253d9-89a4-4daa-87b6-1168369f0b21}</Data>
  </EventData>
</Event>

To add this CLSID to the existing policy, follow these steps:

  1. Open PowerShell ISE with Administrative privileges.

  2. Copy and edit this command, then run it from the admin PowerShell ISE. Consider the policy name to be WDAC_policy.xml.

    PS C:\WINDOWS\system32> Set-CIPolicySetting -FilePath <path to policy xml>\WDAC_policy.xml -Key "{f8d253d9-89a4-4daa-87b6-1168369f0b21}" -Provider WSH -Value true -ValueName EnterpriseDefinedClsId -ValueType Boolean
    

    Once the command has been run, you will find that the following section is added to the policy XML.

    <Settings>
      <Setting Provider="WSH" Key="{f8d253d9-89a4-4daa-87b6-1168369f0b21}" ValueName="EnterpriseDefinedClsId">
        <Value>
          <Boolean>true</Boolean>
        </Value>
      </Setting>
    

Default COM Object Allow List

The table below describes the list of COM objects that are inherently trusted in Windows Defender Application Control. Objects in this list do not need to be allowlisted in your WDAC policies. They can be denied by creating explicit deny rules in your WDAC policy.

File Name CLSID
scrrun.dll EE09B103-97E0-11CF-978F-00A02463E06F
scrrun.dll 0D43FE01-F093-11CF-8940-00A0C9054228
vbscript.dll 3F4DACA4-160D-11D2-A8E9-00104B365C9F
WEX.Logger.Log 70B46225-C474-4852-BB81-48E0D36F9A5A
TE.Common.TestData 1d68f3c0-b5f8-4abd-806a-7bc57cdce35a
TE.Common.RuntimeParameters 9f3d4048-6028-4c5b-a92d-01bc977af600
TE.Common.Verify e72cbabf-8e48-4d27-b14e-1f347f6ec71a
TE.Common.Interruption 5850ba6f-ce72-46d4-a29b-0d3d9f08cc0b
msxml6.dll 2933BF90-7B36-11d2-B20E-00C04F983E60
msxml6.dll ED8C108E-4349-11D2-91A4-00C04F7969E8
mmcndmgr.dll ADE6444B-C91F-4E37-92A4-5BB430A33340
puiobj.dll B021FF57-A928-459C-9D6C-14DED0C9BED2
wdtf.dll 041E868E-0C7D-48C6-965F-5FD576530E5B
wdtfedtaction.dll 0438C02B-EB9C-4E42-81AD-407F6CD6CDE1
wdtfioattackaction.dll 078B1F7D-C34C-4B13-A7C3-9663901650F1
wdtfmutt2tcdsimpleioaction.dll 0ABB2961-2CC1-4F1D-BE8E-9D330D06B77D
wdtfdriverpackageaction.dll 0D7237E6-930F-4682-AD0A-52EBFFD3AEE3
wdtf.dll 0D972387-817B-46E7-913F-E9993FF401EB
wdtf.dll 0E770B12-7221-4A5D-86EE-77310A5506BB
wdtfdriversetupdeviceaction.dll 0FA57208-5100-4CD6-955C-FE69F8898973
wdtf.dll 1080A020-2B47-4DA9-8095-DBC9CEFFFC04
wdtfnetworksimpleioaction.dll 10CF2E12-1681-4C53-ADC0-932C84832CD8
wdtf.dll 140F2286-3B39-4DE1-AF94-E083DEEA6BB9
wdtfinterfaces.dll 1A7D6D61-4FE5-42E2-8F23-4FC1731C474F
wdtfaudiosimpleioaction.dll 1C658D42-4256-4743-A4C5-90BF3A3A186A
wdtf.dll 2236B1F3-4A33-48C2-B22C-A1F93A626F05
wdtfsystemaction.dll 23440924-1AB0-41F2-A732-B75069E5C823
wdtfdriversetupsystemaction.dll 238C0AEB-1DFC-4575-AAF3-C67FE15C1819
wdtffuzztestaction.dll 23D0E542-0390-4873-9AC7-EF86E95E5215
wdtf.dll 240FA08C-1D70-40CB-BDB3-2CC41A45496B
wdtf.dll 26CC4211-A9A6-4E5C-A30D-3C659BB4CDC9
wdtf.dll 28EE5F0B-97D8-4A59-BAC8-A8A80E11F56B
wdtf.dll 2C9AF7D6-2589-4413-A2BA-9926EBCFD67C
wdtf.dll 32A9798D-987F-489E-8DB6-2EFB240248BD
wdtfinterfaces.dll 3C0B0D50-611A-4368-AC87-4488D6E0C4A7
wdtfcdromsimpleioaction.dll 3F2C07F3-199B-4165-A948-B8B59A97FCC5
wdtf.dll 485785D3-8820-4C3D-A532-4C0F66392A30
wdtfinterfaces.dll 5EAE59BE-6946-44B7-A7B3-1D59811B246A
wdtfiospyaction.dll 698F6A82-7833-4499-8BA5-2145D604ABD4
wdtfdevicesupportaction.dll 69D94D1B-0833-40D4-9AE7-7FC6F64F2624
wdtf.dll 6EE5B280-3B0F-4358-9E20-99F169FAA700
wdtfmuttsimpleioaction.dll 7776915A-0370-49A7-90B7-20EB36E80B6D
wdtfcpuutilizationsystemaction.dll 7926C7DE-299C-4B09-BB1B-649A4B917ED0
wdtfwirelesssimpleioaction.dll 7A686BCD-9203-435C-8B06-9D7E7A518F98
wdtfbluetoothsimpleioaction.dll 7E6C4615-6184-4077-A150-5D30F29993A4
wdtf.dll 9663A00A-5B72-4810-9014-C77108062949
wdtfinterfaces.dll 9C261B2B-DBD6-4087-B636-ABE1607989E8
wdtfwebcamsimpleioaction.dll A1B74619-F02D-4574-8091-2AADD46A5B2B
wdtf.dll A2FD15D7-64F0-4080-AABD-884380202022
wdtfvolumesimpleioaction.dll AC91E813-B116-4676-AE33-2988B590F3C7
wdtfconcurrentioaction.dll AE278430-ABC2-49D1-AF30-910B9A88CB1E
wdtf.dll B43FF7F1-629C-4DE5-9559-1D09E0A07037
wdtfdriververifiersystemaction.dll B7770265-B643-4600-A60B-93F9BA9F4B24
wdtfpnpaction.dll B8D74985-4EB9-46AA-B2ED-DD2D918849DF
wdtfmobilebroadbandsimpleioaction.dll BCFBBB02-4DA5-466C-9DA7-DC672877B075
wdtf.dll BE56FAD1-A489-4508-ABB7-3348E1C2C885
wdtfpnpaction.dll C0B6C572-D37D-47CC-A89D-E6B9E0852764
wdtfioattackaction.dll C88B324E-6B26-49BC-9D05-A221F15D7E13
wdtfsensorsiosimpleioaction.dll C8BF7EC0-C746-4DE8-BA46-34528C6329FB
wdtfanysimpleioaction.dll C8C574DA-367B-4130-AED6-1EA61A5C6A4B
simpleio_d3dtest.dll CBC36BDB-A6BC-4383-8194-659470553488
wdtfsystemaction.dll D30E1E07-AA39-4086-A7E6-9245FBD0A730
wdtf.dll DD34E741-139D-4F4C-A1E2-D4184FCDD4F9
wdtfsupaction.dll EA48171B-4265-48C3-B56B-70B175A7FDFA
wdtfinterfaces.dll EB9DB874-D23D-44D5-A988-85E966322843
wdtfinterfaces.dll ED05EF76-09A9-4409-90CA-C5D0711CA057
wdtfwpdsimpleioaction.dll EEA17F2B-8E8E-41A3-9776-A87FACD625D0
wdtfinterfaces.dll F30FC2BB-F424-4A1F-8F95-68CFEE935E92
wdtfedtaction.dll F6694E02-5AD0-476D-BD2D-43F7E5D10AF6
wdtfsmartcardreadersimpleioaction.dll FA6F7E49-76C6-490C-B50E-8B1E8E0EEE2A
wdtfiospyaction.dll FE36026D-CDA8-4514-B3D9-57BDA3870D0C