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Azure security baseline for Azure Web Application Firewall

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This security baseline applies guidance from the Microsoft cloud security benchmark version 1.0 to Azure Web Application Firewall. The Microsoft cloud security benchmark provides recommendations on how you can secure your cloud solutions on Azure. The content is grouped by the security controls defined by the Microsoft cloud security benchmark and the related guidance applicable to Azure Web Application Firewall.

You can monitor this security baseline and its recommendations using Microsoft Defender for Cloud. Azure Policy definitions will be listed in the Regulatory Compliance section of the Microsoft Defender for Cloud portal page.

When a feature has relevant Azure Policy Definitions, they are listed in this baseline to help you measure compliance with the Microsoft cloud security benchmark controls and recommendations. Some recommendations may require a paid Microsoft Defender plan to enable certain security scenarios.

Note

Features not applicable to Azure Web Application Firewall have been excluded. To see how Azure Web Application Firewall completely maps to the Microsoft cloud security benchmark, see the full Azure Web Application Firewall security baseline mapping file.

Security profile

The security profile summarizes high-impact behaviors of Azure Web Application Firewall, which may result in increased security considerations.

Service Behavior Attribute Value
Product Category Networking, Security, Web
Customer can access HOST / OS No Access
Service can be deployed into customer's virtual network True
Stores customer content at rest False

Network security

For more information, see the Microsoft cloud security benchmark: Network security.

NS-1: Establish network segmentation boundaries

Features

Virtual Network Integration

Description: Service supports deployment into customer's private Virtual Network (VNet). Learn more.

Supported Enabled By Default Configuration Responsibility
True True Microsoft

Configuration Guidance: No additional configurations are required as this is enabled on a default deployment.

Network Security Group Support

Description: Service network traffic respects Network Security Groups rule assignment on its subnets. Learn more.

Supported Enabled By Default Configuration Responsibility
True False Customer

Configuration Guidance: Use network security groups (NSG) to restrict or monitor traffic by port, protocol, source IP address, or destination IP address. Create NSG rules to restrict your service's open ports (such as preventing management ports from being accessed from untrusted networks). Be aware that by default, NSGs deny all inbound traffic but allow traffic from virtual network and Azure Load Balancers.

Microsoft Defender for Cloud monitoring

Azure Policy built-in definitions - Microsoft.Network:

Name
(Azure portal)		 Description Effect(s) Version
(GitHub)
Subnets should be associated with a Network Security Group Protect your subnet from potential threats by restricting access to it with a Network Security Group (NSG). NSGs contain a list of Access Control List (ACL) rules that allow or deny network traffic to your subnet. AuditIfNotExists, Disabled 3.0.0

NS-2: Secure cloud services with network controls

Features

Description: Service native IP filtering capability for filtering network traffic (not to be confused with NSG or Azure Firewall). Learn more.

Supported Enabled By Default Configuration Responsibility
True False Customer

Feature notes: For more information, please visit Secure your Origin with Private Link in Azure Front Door Premium and Configure Azure Application Gateway Private Link.

Configuration Guidance: Deploy private endpoints for all Azure resources that support the Private Link feature, to establish a private access point for the resources.

Disable Public Network Access

Description: Service supports disabling public network access either through using service-level IP ACL filtering rule (not NSG or Azure Firewall) or using a 'Disable Public Network Access' toggle switch. Learn more.

Supported Enabled By Default Configuration Responsibility
True False Customer

Feature notes: In the regional WAF offering customers have the option to use private IPs and deny public IP traffic.

Configuration Guidance: Disable public network access either using the service-level IP ACL filtering rule or a toggling switch for public network access.

Reference: Private Application Gateway deployment

Privileged access

For more information, see the Microsoft cloud security benchmark: Privileged access.

PA-8: Determine access process for cloud provider support

Features

Customer Lockbox

Description: Customer Lockbox can be used for Microsoft support access. Learn more.

Supported Enabled By Default Configuration Responsibility
False Not Applicable Not Applicable

Configuration Guidance: This feature is not supported to secure this service.

Data protection

For more information, see the Microsoft cloud security benchmark: Data protection.

DP-1: Discover, classify, and label sensitive data

Features

Sensitive Data Discovery and Classification

Description: Tools (such as Azure Purview or Azure Information Protection) can be used for data discovery and classification in the service. Learn more.

Supported Enabled By Default Configuration Responsibility
True False Customer

Feature notes: Customers can run these tools on their logs within Log Analytics, but the WAF itself does not store any sensitive customer data to be discovered and classified.

Additionally, there is a feature within WAF that allows identification and masking of sensitive data.

Configuration Guidance: The Web Application Firewall's (WAF's) Log Scrubbing tool helps you remove sensitive data from your WAF logs. It works by using a rules engine that allows you to build custom rules to identify specific portions of a request that contain sensitive data. Once identified, the tool scrubs that information from your logs and replaces it with *******.

Reference: How to mask sensitive data on Azure Web Application Firewall

DP-3: Encrypt sensitive data in transit

Features

Data in Transit Encryption

Description: Service supports data in-transit encryption for data plane. Learn more.

Supported Enabled By Default Configuration Responsibility
True False Customer

Feature notes: For more information, please visit Configure HTTPS on an Azure Front Door custom domain using the Azure portal, How to configure an origin for Azure Front Door, and Overview of TLS termination and end to end TLS with Application Gateway.

Configuration Guidance: Enable secure transfer in services where there is a native data in transit encryption feature built in. Enforce HTTPS on any web applications and services and ensure TLS v1.2 or later is used. Legacy versions such as SSL 3.0, TLS v1.0 should be disabled. For remote management of Virtual Machines, use SSH (for Linux) or RDP/TLS (for Windows) instead of an unencrypted protocol.

DP-7: Use a secure certificate management process

Features

Certificate Management in Azure Key Vault

Description: The service supports Azure Key Vault integration for any customer certificates. Learn more.

Supported Enabled By Default Configuration Responsibility
True False Customer

Feature notes: The WAF supports Key Vault integration for certificates via Azure Front Door and Application Gateway depending on which version of the WAF the customer is running.

For more information, please visit: Quickstart: Create an Azure Front Door profile - Azure portal and Tutorial: Configure HTTPS on an Azure CDN custom domain.

Configuration Guidance: Use Azure Key Vault to create and control the certificate lifecycle, including creation, importing, rotation, revocation, storage, and purging of the certificate. Ensure the certificate generation follows defined standards without using any insecure properties, such as: insufficient key size, overly long validity period, insecure cryptography. Setup automatic rotation of the certificate in Azure Key Vault and the Azure service (if supported) based on a defined schedule or when there is a certificate expiration. If automatic rotation is not supported in the application, ensure they are still rotated using manual methods in Azure Key Vault and the application.

Reference: TLS termination with Key Vault certificates

Asset management

For more information, see the Microsoft cloud security benchmark: Asset management.

AM-2: Use only approved services

Features

Azure Policy Support

Description: Service configurations can be monitored and enforced via Azure Policy. Learn more.

Supported Enabled By Default Configuration Responsibility
True False Customer

Feature notes: Customers will need to choose which Azure Policies to enable on their WAF deployments; they do not come enabled by default.

Configuration Guidance: Use Microsoft Defender for Cloud to configure Azure Policy to audit and enforce configurations of your Azure resources. Use Azure Monitor to create alerts when there is a configuration deviation detected on the resources. Use Azure Policy [deny] and [deploy if not exists] effects to enforce secure configuration across Azure resources.

Reference: Azure Web Application Firewall and Azure Policy

Logging and threat detection

For more information, see the Microsoft cloud security benchmark: Logging and threat detection.

LT-1: Enable threat detection capabilities

Features

Microsoft Defender for Service / Product Offering

Description: Service has an offering-specific Microsoft Defender solution to monitor and alert on security issues. Learn more.

Supported Enabled By Default Configuration Responsibility
True False Customer

Configuration Guidance: Use Azure Active Directory (Azure AD) as the default authentication method to control your management plane access. When you get an alert from Microsoft Defender for Key Vault, investigate and respond to the alert.

Reference: Display Azure WAF alerts in Defender for Cloud

LT-4: Enable logging for security investigation

Features

Azure Resource Logs

Description: Service produces resource logs that can provide enhanced service-specific metrics and logging. The customer can configure these resource logs and send them to their own data sink like a storage account or log analytics workspace. Learn more.

Supported Enabled By Default Configuration Responsibility
True False Customer

Feature notes: For more information, please visit Azure Web Application Firewall monitoring and logging and Azure Web Application Firewall Monitoring and Logging.

Configuration Guidance: Enable resource logs for the service. For example, Key Vault supports additional resource logs for actions that get a secret from a key vault or and Azure SQL has resource logs that track requests to a database. The content of resource logs varies by the Azure service and resource type.

Next steps