Description

Ensure that the latest OS patches for all virtual machines are applied.

Rationale

Windows and Linux virtual machines should be kept updated to:

• Address a specific bug or flaw
• Improve an OS or application’s general stability
• Fix a security vulnerability

Microsoft Defender for Cloud retrieves a list of available security and critical updates from Windows Update or Windows Server Update Services (WSUS), depending on which service is configured on a Windows VM. The security center also checks for the latest updates in Linux systems. If a VM is missing a system update, the security center will recommend system updates be applied.

Impact

Running Microsoft Defender for Cloud incurs additional charges for each resource monitored. Please see attached reference for exact charges per hour.

Audit

From Azure Portal

1. From Azure Home select the Portal Menu.
2. Select Microsoft Defender for Cloud.
3. Then the Recommendations blade.
4. Ensure that there are no recommendations for Apply system updates.

Alternatively, you can employ your own patch assessment and management tool to periodically assess, report and install the required security patches for your OS.

From Azure Policy

If referencing a digital copy of this Benchmark, clicking a Policy ID will open a link to the associated Policy definition in Azure.

• Policy ID: bd876905-5b84-4f73-ab2d-2e7a7c4568d9 - Name: [Preview]: Machines should be configured to periodically check for missing system updates

Default Value

By default, patches are not automatically deployed.

References

1. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-posture-vulnerability-management#pv-6-rapidly-and-automatically-remediate-vulnerabilities
2. https://azure.microsoft.com/en-us/pricing/details/defender-for-cloud/
3. https://docs.microsoft.com/en-us/azure/defender-for-cloud/deploy-vulnerability-assessment-vm