Control: 9.7 Ensure that '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 services is recommended to avoid potential unpatched vulnerabilities.

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

Remediation

From Azure Portal

From Azure Home open the Portal Menu in the top left.
Go to App Services.
Click on each App.
Under Settings section, click on Configuration.
Click on the General settings pane, ensure that for a Stack of PHP the Major Version and Minor Version reflect a currently supported release.

NOTE: No action is required If PHP version is set to Off or is set with an empty value as PHP is not used by your app.

From Azure CLI

List the available PHP runtimes:

az webapp list-runtimes

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

az webapp config set --resource-group <RESOURCE_GROUP_NAME> --name <APP_NAME> [--linux-fx-version <PHP_RUNTIME_VERSION>][--php-version <PHP_VERSION>]

From Powershell

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

Set-AzWebApp -ResourceGroupName <RESOURCE_GROUP_NAME> -Name <APP_NAME> -phpVersion <PHP_VERSION>

NOTE: Currently there is no way to update an existing web app Linux FX Version setting using PowerShell, nor is there a way to create a new web app using PowerShell that configures the PHP runtime in the Linux FX Version setting.

Default Value

The version of PHP is whatever was selected upon App creation.

Usage

Run the control in your terminal:

powerpipe control run azure_compliance.control.cis_v300_9_7

Snapshot and share results via Turbot Pipes:

powerpipe login
powerpipe control run azure_compliance.control.cis_v300_9_7 --share

SQL

This control uses a named query:

with all_web_app as (
  select
    id
  from
    azure_app_service_web_app
  where
    exists (
      select
      from
        unnest(regexp_split_to_array(kind, ',')) elem
      where
        elem like 'app%'
    )
    and
    exists (
      select
      from
        unnest(regexp_split_to_array(kind, ',')) elem
      where
        elem = 'linux'
    )
)
select
  a.id as resource,
  case
    when b.id is null then 'skip'
    when configuration -> 'properties' ->> 'linuxFxVersion' not like 'PHP%' then 'ok'
    when configuration -> 'properties' ->> 'linuxFxVersion' = $1 then 'ok'
    else 'alarm'
  end as status,
  case
    when b.id is null then a.title || ' is ' || a.kind || ' kind.'
    when configuration -> 'properties' ->> 'linuxFxVersion' not like 'PHP%' then a.name ||  ' not using php version.'
    when configuration -> 'properties' ->> 'linuxFxVersion' = $1 then a.name || ' using the latest php version.'
    else a.name || ' not using latest php version.'
  end as reason
  
  , a.resource_group as resource_group
  , sub.display_name as subscription
from
  azure_app_service_web_app as a
  left join all_web_app as b on a.id = b.id
  left join azure_subscription as sub on sub.subscription_id = a.subscription_id;

Params

Args	Name	Default	Description	Variable
$1	appservice_web_app_latest_php_version	`PHP\|8.4`	AppService web app latest PHP version.	appservice_web_app_latest_php_version