Cis Azure Compute 2.1.1

Ensure 'Java version' is currently supported (if in use)

Description

Periodically, older versions of Java may be deprecated and no longer supported. Using a supported version of Java for App Service apps is recommended to avoid potential unpatched vulnerabilities.

Rationale

Deprecated and unsupported versions of programming and scripting languages can present vulnerabilities which may not be addressed or may not be addressable.

Impact

If your app is written using version-dependent features or libraries, they may not be available on more recent versions. If you wish to update, research the impact thoroughly.

Audit Procedure

Using Azure Portal

1. Go to App Services.
2. Click the name of an app.
3. Under Settings, click Configuration.
4. In the General settings pane, ensure that for a Stack of Java, the Major Version and Minor Version reflect a currently supported release, and that the Java web server version is set to the auto-update option.
5. Repeat steps 1-4 for each app.

NOTE: No action is required if Java version is set to Off, as Java is not used by your app.

Using Azure CLI

Run the following command to list apps:

az webapp list

For each app, run the following command to check the Java version:

az webapp config show --resource-group <resource-group-name> --name <app-name> --query "{LinuxFxVersion:linuxFxVersion, WindowsFxVersion:windowsFxVersion, JavaVersion:javaVersion, JavaContainerVersion:javaContainerVersion, JavaContainer:javaContainer}"

If Java is in use, ensure the version is currently supported.

Using Azure PowerShell

For each application, store the application information within an object, and then interrogate the SiteConfig information for that application object:

$app = Get-AzWebApp -Name <app-name> -ResourceGroup <resource-group-name>

$app.SiteConfig |Select-Object LinuxFXVersion, WindowsFxVersion, JavaVersion, JavaContainerVersion, JavaContainer

If Java is in use, ensure the version is currently supported.

Expected Result

The Java version in use should be a currently supported release as listed at https://www.oracle.com/java/technologies/java-se-support-roadmap.html.

Remediation

Using Azure Portal

1. Login to Azure Portal using https://portal.azure.com
2. Go to App Services
3. Click on each App
4. Under Settings section, click on Configuration
5. Click on the General settings pane and ensure that for a Stack of Java the Major Version and Minor Version reflect a currently supported release, and that the Java web server version is set to the auto-update option.

NOTE: No action is required if Java version is set to Off, as Java is not used by your app.

Using Azure CLI

To see the list of supported runtimes:

az webapp list-runtimes

To set a currently supported Java version for an existing app, run the following command:

az webapp config set --resource-group <RESOURCE_GROUP_NAME> --name <APP_NAME> [--java-version <JAVA_VERSION> --java-container <JAVA_CONTAINER> --java-container-version <JAVA_CONTAINER_VERSION> [--windows-fx-version <JAVA_RUNTIME_VERSION>] [--linux-fx-version <JAVA_RUNTIME_VERSION>]

If creating a new application to use a currently supported version of Java, run the following commands.

To create an app service plan:

az appservice plan create --resource-group <RESOURCE_GROUP_NAME> --name <PLAN_NAME> --location <LOCATION> [--is-linux --number-of-workers <INT> --sku <PRICING_TIER>] [--hyper-v --sku <PRICING_TIER>]

Get the app service plan ID:

az appservice plan list --query "[].{Name:name, ID:id, SKU:sku, Location:location}"

To create a new Java web application using the retrieved app service ID:

az webapp create --resource-group <RESOURCE_GROUP_NAME> --plan <APP_SERVICE_PLAN_ID> --name <app name> [--linux-fx-version <JAVA_RUNTIME_VERSION>] [--windows-fx-version <JAVA_RUNTIME_VERSION>]

Using Azure PowerShell

As of this writing, there is no way to update an existing application's SiteConfig or set a new application's SiteConfig settings during creation via PowerShell.

Default Value

The version is selected during creation.

References

1. https://learn.microsoft.com/en-us/azure/app-service/configure-language-java-deploy-run
2. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-posture-vulnerability-management#pv-3-define-and-establish-secure-configurations-for-compute-resources
3. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-posture-vulnerability-management#pv-6-rapidly-and-automatically-remediate-vulnerabilities
4. https://www.oracle.com/java/technologies/java-se-support-roadmap.html
5. https://learn.microsoft.com/en-us/cli/azure/webapp

Profile

Level 1 | Manual