7.4 Ensure that Only Approved Extensions Are Installed

Warning! Audit Deprecated

This audit has been deprecated and will be removed in a future update.

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Information

For added security, only install organization-approved extensions on VMs.

Rationale:

Azure virtual machine extensions are small applications that provide post-deployment configuration and automation tasks on Azure virtual machines. These extensions run with administrative privileges and could potentially access anything on a virtual machine. The Azure Portal and community provide several such extensions. Each organization should carefully evaluate these extensions and ensure that only those that are approved for use are actually implemented.

Impact:

Functionality by unsupported extensions will be disabled.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

From Azure Console

Go to Virtual machines

For each virtual machine, go to Settings

Click on Extensions + applications

If there are unapproved extensions, uninstall them.

From Azure Command Line Interface 2.0
From the audit command identify the unapproved extensions, and use the below CLI command to remove an unapproved extension attached to VM.

az vm extension delete --resource-group <resourceGroupName> --vm-name <vmName> --name <extensionName>

Using PowerShell
For each VM and each unsecured extension from the Audit Procedure run the following command.

Remove-AzVMExtension -ResourceGroupName <ResourceGroupName> -Name <ExtensionName> -VMName <VirtualMachineName>

Default Value:

By default, no extensions are added to the virtual machines.

See Also

https://workbench.cisecurity.org/files/4052