Some capabilities of Windows Defender Application Control are only available on specific Windows versions. Learn more about the Windows Defender Application Control feature availability.
This article provides a description of AppLocker and can help you decide if your organization can benefit from deploying AppLocker application control policies. AppLocker helps you control which apps and files users can run. These include executable files, scripts, Windows Installer files, dynamic-link libraries (DLLs), packaged apps, and packaged app installers.
AppLocker is unable to control processes running under the system account on any operating system.
AppLocker can help you:
- Define rules based on file attributes that persist across app updates, such as the publisher name (derived from the digital signature), product name, file name, and file version. You can also create rules based on the file path and hash.
- Assign a rule to a security group or an individual user.
- Create exceptions to rules. For example, you can create a rule that allows all users to run all Windows binaries, except the Registry Editor (regedit.exe).
- Use audit-only mode to deploy the policy and understand its impact before enforcing it.
- Create rules on a staging server, test them, then export them to your production environment and import them into a Group Policy Object.
- Simplify creating and managing AppLocker rules by using Windows PowerShell.
AppLocker helps reduce administrative overhead and helps reduce the organization's cost of managing computing resources by decreasing the number of Help Desk calls that result from users running unapproved apps. AppLocker addresses the following app security scenarios:
- Application inventory: AppLocker has the ability to enforce its policy in an audit-only mode where all app access activity is registered in event logs. These events can be collected for further analysis. Windows PowerShell cmdlets also help you analyze this data programmatically.
- Protection against unwanted software: AppLocker has the ability to deny apps from running when you exclude them from the list of allowed apps. When AppLocker rules are enforced in the production environment, any apps that aren't included in the allowed rules are blocked from running.
- Licensing conformance: AppLocker can help you create rules that preclude unlicensed software from running and restrict licensed software to authorized users.
- Software standardization: AppLocker policies can be configured to allow only supported or approved apps to run on computers within a business group. This configuration permits a more uniform app deployment.
- Manageability improvement: AppLocker includes many improvements in manageability as compared to its predecessor Software Restriction Policies. Importing and exporting policies, automatic generation of rules from multiple files, audit-only mode deployment, and Windows PowerShell cmdlets are a few of the improvements over Software Restriction Policies.
When to use AppLocker
In many organizations, information is the most valuable asset, and ensuring that only approved users have access to that information is imperative. Access control technologies, such as Active Directory Rights Management Services (AD RMS) and access control lists (ACLs), help control what users are allowed to access.
However, when a user runs a process, that process has the same level of access to data that the user has. As a result, sensitive information could easily be deleted or transmitted out of the organization if a user knowingly or unknowingly runs malicious software. AppLocker can help mitigate these types of security breaches by restricting the files that users or groups are allowed to run. Software publishers are beginning to create more apps that can be installed by non-administrative users. This privilege could jeopardize an organization's written security policy and circumvent traditional app control solutions that rely on the inability of users to install apps. AppLocker creates an allowed list of approved files and apps to help prevent such per-user apps from running. Because AppLocker can control DLLs, it's also useful to control who can install and run ActiveX controls.
AppLocker is ideal for organizations that currently use Group Policy to manage their PCs.
The following are examples of scenarios in which AppLocker can be used:
- Your organization's security policy dictates the use of only licensed software, so you need to prevent users from running unlicensed software and also restrict the use of licensed software to authorized users.
- An app is no longer supported by your organization, so you need to prevent it from being used by everyone.
- The potential that unwanted software can be introduced in your environment is high, so you need to reduce this threat.
- The license to an app has been revoked or it's expired in your organization, so you need to prevent it from being used by everyone.
- A new app or a new version of an app is deployed, and you need to prevent users from running the old version.
- Specific software tools aren't allowed within the organization, or only specific users should have access to those tools.
- A single user or small group of users needs to use a specific app that is denied for all others.
- Some computers in your organization are shared by people who have different software usage needs, and you need to protect specific apps.
- In addition to other measures, you need to control the access to sensitive data through app usage.
AppLocker is a defense-in-depth security feature and not a security boundary. Windows Defender Application Control should be used when the goal is to provide robust protection against a threat and there are expected to be no by-design limitations that would prevent the security feature from achieving this goal.
AppLocker can help you protect the digital assets within your organization, reduce the threat of malicious software being introduced into your environment, and improve the management of application control and the maintenance of application control policies.
AppLocker is included with enterprise-level editions of Windows. You can author AppLocker rules for a single computer or for a group of computers. For a single computer, you can author the rules by using the Local Security Policy editor (secpol.msc). For a group of computers, you can author the rules within a Group Policy Object by using the Group Policy Management Console (GPMC).
GPMC is available in client computers running Windows only by installing the Remote Server Administration Tools. On computer running Windows Server, you must install the Group Policy Management feature.
Using AppLocker on Server Core
AppLocker on Server Core installations isn't supported.
You can administer AppLocker policies by using a virtualized instance of Windows provided it meets all the system requirements listed previously. You can also run Group Policy in a virtualized instance. However, you do risk losing the policies that you created and maintain if the virtualized instance is removed or fails.
Application control policies specify which apps are allowed to run on the local computer. The variety of forms that malicious software can take make it difficult for users to know what is safe to run. When activated, malicious software can damage content on a hard disk drive, flood a network with requests to cause a denial-of-service (DoS) attack, send confidential information to the Internet, or compromise the security of a computer.
The countermeasure is to create a sound design for your application control policies on PCs in your organization, and then thoroughly test the policies in a lab environment before you deploy them in a production environment. AppLocker can be part of your app control strategy because you can control what software is allowed to run on your computers.
A flawed application control policy implementation can disable necessary applications or allow malicious or unintended software to run. Therefore, it's important that organizations dedicate sufficient resources to manage and troubleshoot the implementation of such policies.
For more information about specific security issues, see Security considerations for AppLocker. When you use AppLocker to create application control policies, you should be aware of the following security considerations:
- Who has the rights to set AppLocker policies?
- How do you validate that the policies are enforced?
- What events should you audit?
For reference in your security planning, the following table identifies the baseline settings for a PC with AppLocker installed:
|Authentication method||Not applicable|
|Management interfaces||AppLocker can be managed by using a Microsoft Management Console snap-in, Group Policy Management, and Windows PowerShell|
|Minimum privileges required||Administrator on the local computer; Domain Admin, or any set of rights that allow you to create, edit and distribute Group Policy Objects.|
|Protocols used||Not applicable|
|Scheduled Tasks||Appidpolicyconverter.exe is put in a scheduled task to be run on demand.|
|Security Policies||None required. AppLocker creates security policies.|
|System Services required||Application Identity service (appidsvc) runs under LocalServiceAndNoImpersonation.|
|Storage of credentials||None|
In this section
|Administer AppLocker||This article for IT professionals provides links to specific procedures to use when administering AppLocker policies.|
|AppLocker design guide||This article for the IT professional introduces the design and planning steps required to deploy application control policies by using AppLocker.|
|AppLocker deployment guide||This article for IT professionals introduces the concepts and describes the steps required to deploy AppLocker policies.|
|AppLocker technical reference||This overview article for IT professionals provides links to the articles in the technical reference.|