^{CVE-2020-1043:}Hyper-V RemoteFX vGPU Remote Code Execution Vulnerability

Overview

This vulnerability affects Microsoft Hyper-V's RemoteFX vGPU feature, which allows virtual machines to access the physical GPU on the host server for enhanced graphics performance. The vulnerability is classified as CWE-20 (Improper Input Validation), indicating that the issue stems from the system's failure to properly validate or sanitize input data.

An authenticated user with access to a guest operating system could potentially send specially crafted input to the RemoteFX vGPU component, bypassing validation mechanisms. If successfully exploited, this could allow the attacker to execute arbitrary code on the host server with elevated privileges, potentially compromising the entire virtualization infrastructure and all guest operating systems running on the affected host.

The vulnerability requires authentication to a guest VM, which limits the attack surface somewhat, but the potential impact is severe given that successful exploitation could lead to complete host compromise.

Remediation

To address this vulnerability, system administrators should take the following actions:

1. Apply the security update released by Microsoft as soon as possible. This update is available through Windows Update or can be downloaded from the Microsoft Update Catalog.

2. Microsoft has disabled RemoteFX vGPU by default as a security measure. If you are using RemoteFX vGPU, you should consider alternative solutions for GPU virtualization.

3. If you cannot immediately apply the update, consider temporarily disabling RemoteFX vGPU functionality on affected Hyper-V hosts until the update can be applied.

4. Ensure that only trusted users have access to guest virtual machines, as the vulnerability requires authentication to a guest OS.

5. Monitor your Hyper-V hosts for unusual activity that could indicate exploitation attempts.

6. If you are using NVIDIA GPUs with Hyper-V, also check for and apply any related updates from NVIDIA, as referenced in their advisory.

References

1. Microsoft Security Advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1043

2. NVIDIA Advisory: https://nvidia.custhelp.com/app/answers/detail/a_id/5044

3. Microsoft Security Update Guide: https://msrc.microsoft.com/update-guide/

4. Common Weakness Enumeration (CWE-20): https://cwe.mitre.org/data/definitions/20.html