Cis Azure Compute 2.2.3

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

Description

Periodically, older versions of PHP may be deprecated and no longer supported. Using a supported version of PHP for App Service deployment slots 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

Take note of the currently supported versions of PHP here: https://www.php.net/supported-versions.php

Using Azure Portal

1. Go to App Services.
2. Click the name of an app.
3. Under Deployment, click Deployment slots.
4. Click the name of a deployment slot.
5. Under Settings, click Configuration.
6. In the General settings pane, ensure that for a Stack of PHP, the Major version and Minor version reflect a currently supported release.
7. Repeat steps 1-6 for each app and deployment slot.

Using Azure CLI

Run the following command to list apps:

az webapp list

For each app, run the following command to list deployment slots:

az webapp deployment slot list --resource-group <resource-group-name> --name <app-name>

For each deployment slot, run the following command to get the PHP version:

az resource show --name web --resource-group <resource-group-name> --namespace Microsoft.Web --resource-type config --parent sites/<app-name>/slots/<deployment-slot-name> --query properties.[linuxFxVersion,phpVersion]

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

Expected Result

The PHP version configured for the deployment slot should be a currently supported release as listed on the PHP Supported Versions page.

Remediation

Note: No action is required if PHP is not in use.

Using Azure Portal

1. Go to App Services.
2. Click the name of an app.
3. Under Deployment, click Deployment slots.
4. Click the name of a deployment slot.
5. Under Settings, click Configuration.
6. In the General settings pane, for a Stack of PHP, set the Major version and Minor version to a currently supported release.
7. Click Save.
8. Click Continue.
9. Repeat steps 1-8 for each app and deployment slot requiring remediation.

Using Azure CLI

Run the following command to list supported runtimes:

az webapp list-runtimes

For each deployment slot requiring remediation, run the following command with the appropriate parameters to update the PHP version:

az resource update --name web --resource-group <resource-group-name> --namespace Microsoft.Web --resource-type config --parent sites/<app-name>/slots/<deployment-slot-name> --set properties.[linuxFxVersion|phpVersion]="<python-runtime-version|python-version>"

Default Value

The version is selected during creation.

References

1. https://learn.microsoft.com/en-us/azure/app-service/configure-common#general-settings
2. https://learn.microsoft.com/en-us/security/benchmark/azure/security-controls-v3-posture-vulnerability-management#pv-7-rapidly-and-automatically-remediate-software-vulnerabilities
3. https://learn.microsoft.com/en-us/security/benchmark/azure/security-controls-v3-posture-vulnerability-management#pv-3-establish-secure-configurations-for-compute-resources
4. https://www.php.net/supported-versions.php
5. https://learn.microsoft.com/en-us/cli/azure/webapp
6. https://learn.microsoft.com/en-us/cli/azure/resource

Profile

Level 1 | Manual