Cis Azure Foundations 7.13

Ensure 'HTTP2' is set to 'Enabled' on Azure Application Gateway

Description

Enable HTTP/2 for improved performance, efficiency, and security.

HTTP/2 protocol support is available to clients that connect to application gateway listeners only. Communication with backend server pools is always HTTP/1.1.

Rationale

Enabling HTTP/2 supports use of modern encrypted connections.

Impact

Clients and backend services that do not support HTTP/2 will fall back to HTTP/1.1.

Audit Procedure

Using Azure Portal

1. Go to Application gateways.
2. Click the name of an application gateway.
3. Under Settings, click Configuration.
4. Ensure HTTP2 is set to Enabled.
5. Repeat steps 1-4 for each application gateway.

Using Azure CLI

Run the following command to list application gateways:

az network application-gateway list

For each application gateway, run the following command to get the HTTP2 setting:

az network application-gateway show --resource-group <resource-group> --name <application-gateway> --query enableHttp2

Ensure true is returned.

Using PowerShell

Run the following command to list application gateways:

Get-AzApplicationGateway

Run the following command to get the application gateway in a resource group with a given name:

$gateway = Get-AzApplicationGateway -ResourceGroupName <resource-group> -Name <application-gateway>

Run the following command to get the HTTP2 setting:

$gateway.EnableHttp2

Ensure True is returned.

Repeat for each application gateway.

Expected Result

All Application Gateways should have HTTP2 set to Enabled (enableHttp2 = true).

Remediation

Remediate from Azure Portal

1. Go to Application gateways.
2. Click the name of an application gateway.
3. Under Settings, click Configuration.
4. Under HTTP2, click Enabled.
5. Click Save.
6. Repeat steps 1-5 for each application gateway requiring remediation.

Remediate from Azure CLI

For each application gateway requiring remediation, run the following command to enable HTTP2:

az network application-gateway update --resource-group <resource-group> --name <application-gateway> --http2 Enabled

Remediate from PowerShell

Run the following command to get the application gateway in a resource group with a given name:

$gateway = Get-AzApplicationGateway -ResourceGroupName <resource-group> -Name <application-gateway>

Run the following command to enable HTTP2:

$gateway.EnableHttp2 = $true

Run the following command to apply the update:

Set-AzApplicationGateway -ApplicationGateway $gateway

Repeat for each application gateway requiring remediation.

Default Value

HTTP2 is enabled by default.

References

1. https://learn.microsoft.com/en-us/azure/application-gateway/features#websocket-and-http2-traffic
2. https://learn.microsoft.com/en-us/cli/azure/network/application-gateway
3. https://learn.microsoft.com/en-us/powershell/module/az.network/get-azapplicationgateway
4. https://learn.microsoft.com/en-us/powershell/module/az.network/set-azapplicationgateway

CIS Controls

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Level 1 | Automated