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windows/security/threat-protection/windows-defender-application-control/create-wdac-deny-policy.md
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@ -38,7 +38,7 @@ To create effective WDAC deny policies, it is crucial to understand how WDAC par
2. Explicit allow rules.
3. WDAC will then check for the [Managed Installer extended (EA)](configure-authorized-apps-deployed-with-a-managed-installer) or the [Intelligent Security Graph (ISG) EA](https://docs.microsoft.com/en-us/windows/security/threat-protection/windows-defender-application-control/use-windows-defender-application-control-with-intelligent-security-graph) on the file.
3. WDAC will then check for the [Managed Installer extended (EA)](configure-authorized-apps-deployed-with-a-managed-installer.md) or the [Intelligent Security Graph (ISG) EA](use-windows-defender-application-control-with-intelligent-security-graph.md) on the file.
4. Lastly, WDAC will call the Intelligent Security Graph (ISG) to get reputation on file, if the policy has support for the ISG.
@ -90,7 +90,7 @@ If the policy enables user mode code integrity via the ***Enabled:UMCI*** rule-o
</SigningScenarios>
```
## Single Policy Considerations
If the set of deny rules is to be added into an existing policy with allow rules, then the above Allow All rules should not be added to the policy. Instead, the deny policy should be merged with the existing WDAC policy via the WDAC Wizard [Windows Defender Application Control Wizard Policy Merging Operation - Windows security | Microsoft Docs](https://docs.microsoft.com/en-us/windows/security/threat-protection/windows-defender-application-control/wdac-wizard-merging-policies) or using the following PowerShell command:
If the set of deny rules is to be added into an existing policy with allow rules, then the above Allow All rules should not be added to the policy. Instead, the deny policy should be merged with the existing WDAC policy via the WDAC Wizard [Windows Defender Application Control Wizard Policy Merging Operation](windows-defender-application-control/wdac-wizard-merging-policies.md) or using the following PowerShell command:
```PowerShell
$DenyPolicy = <path_to_deny_policy>
@ -105,25 +105,17 @@ If you are currently using [multiple policies](deploy-multiple-windows-defender-
Policy 1 is an allow list of Windows and Microsoft-signed applications. Policy 2 is our new deny policy which blocks MaliciousApp.exe with the Allow All rules. MaliciousApp.exe will be blocked since there is an explicit block rule in Policy 2. Windows and Microsoft applications will be allowed since there is an explicit allow rule in Policy 1 and Policy 2 (due to the Allow All rules). All other applications, if not Windows and Microsoft signed, e.g., ExampleApp.exe, will not be allowed as this application is only trusted by Policy 2 (due to the Allow All rules) and not Policy 1.
The second option involves merging the deny list with your existing WDAC policy, regardless if the policy is an allow list policy and contains allow and/or deny rules.
## Best Practices
1. **Starting with Audit Mode Policies** - as with all new policies, we recommend rolling out your new deny policy in Audit Mode and monitoring the [3077 block events](event-id-explanations.md#microsoft-windows-codeintegrity-operational-log-event-ids) to ensure only the applications you intended to block are being blocked. More information on monitoring block events via the Event Viewer logs and Advanced Hunting: [Managing and troubleshooting Windows Defender Application Control policies](windows-defender-application-control-operational-guide.md)
1. **Starting with Audit Mode Policies** - as with all new policies, we recommend rolling out your new deny policy in Audit Mode and monitoring the [3077 block events](event-id-explanations.md#microsoft-windows-codeintegrity-operational-log-event-ids.md) to ensure only the applications you intended to block are being blocked. More information on monitoring block events via the Event Viewer logs and Advanced Hunting: [Managing and troubleshooting Windows Defender Application Control policies](windows-defender-application-control-operational-guide.md)
2. **Recommeneded Deny Rules Types** - signer and file attribute rules are recommended from a security, manageability, and performance perspective. Hash rules should only be utilized where otherwise impossible. The hash of an application is updated for every new version released by the publisher which quickly becomes impractical to manage and protect against new threats where the attacker is quickly iterating on the payload. Additionally, WDAC has optimized parsing of hash rules, but devices may see performance impacts at runtime evaluation when policies have tens of thousands or more hash rules.
## Creating a Deny Policy Tutorial
Deny rules and policies can be created using the PowerShell cmdlets or the WDAC Wizard [Microsoft WDAC Wizard](https://webapp-wdac-wizard.azurewebsites.net/) We recommend creating signer rules (PCACertificate, Publisher, and FilePublisher) wherever possible. In the cases of unsigned binaries, rules must be created on attributes of the file, such as the original filename, or the hash.
## Tutorial
### Creating a Deny Policy
Deny rules and policies can be created using the PowerShell cmdlets or the [WDAC Wizard](https://webapp-wdac-wizard.azurewebsites.net/) We recommend creating signer rules (PCACertificate, Publisher, and FilePublisher) wherever possible. In the cases of unsigned binaries, rules must be created on attributes of the file, such as the original filename, or the hash.
`d2313afd3e53ed3184ca3c47b7242dd156a935af`
### Software Publisher Based Deny Rule
```Powershell
$DenyRules += New-CIPolicyRule -Level FilePublisher -DriverFilePath <binary_to_block> -Deny -Fallback FileName,Hash
@ -140,7 +132,7 @@ $DenyRules += New-CIPolicyRule -Level FileName -DriverFilePath <binary_to_block>
```
### Adding Allow All Rules
If required, as in the cases listed above, [Allow All Rules](#adding-allow-rules) may need to be added to the policy. The Allow All rules can be manually added to the policy xml or added by merging with the Allow All xml present on the client system in the WDAC template folder:
If required, as in the cases listed above, [Allow All Rules](#adding-allow-rules) may need to be added to the policy. The Allow All rules can be manually added to the policy xml or by merging with the Allow All xml present on the client system in the WDAC template folder:
```PowerShell
$DenyPolicy = <path_to_deny_policy>