Implementing AppLocker – some important steps before you start!

AppLocker is a feature within Windows 7 and Server 2008 R2 which uses rules and properties of files to provide access control for applications.
In an environment where you want to prevent the use of certain applications, or even to deny all applications and only allow the applications you name, AppLocker is the solution for you.

Before you get started, there are some pre requisites which aren’t so obvious. Without configuring the prerequisites detailed in this article, although your be able to configure AppLocker policy’s, and a gpresult will show them as being applied, they will not be.

The first step is to enable AppLocker Rule enforcement. To do this, edit the group policy object which you wish to use to apply the AppLocker policys, and navigate to

Computer Configuration | Policies | Windows Settings | Security Settings | Application Control Policies | Applocker

Select “Configure rule enforcement”

Select all three configured boxes (ensuring that enforce rules is selected from the drop down boxes) and click ok. This now means any policies you put in place will be applied for executable applications, windows installers and scripts.

The next stage is to ensure the “application identity service” is running
This can be done manually on all your workstations, as part of a generic build or via group policy preferences. Group policy is by far the most effective way of doing this so it is detailed here.

Edit the group policy object which you want to use to configure the service, this GPO must apply to all computers you wish to have AppLocker policies applied on

Services can be configured by using Group Policy Preferences, to configure this navigate to:
Computer Configuration | Preferences | Control Panel Settings | Services
Right click ion services and select New | Service

Modify the start-up to be "Automatic" and browse for the service named “Application Identity” ensure the service action is “Start Service” then click ok

Because these are all machine policies, the workstations may need to be rebooted twice for them to take effect.