CVE-2020-1036 in Windows
Summary
by MITRE
A remote code execution vulnerability exists when Hyper-V RemoteFX vGPU on a host server fails to properly validate input from an authenticated user on a guest operating system, aka 'Hyper-V RemoteFX vGPU Remote Code Execution Vulnerability'. This CVE ID is unique from CVE-2020-1032, CVE-2020-1040, CVE-2020-1041, CVE-2020-1042, CVE-2020-1043.
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Analysis
by VulDB Data Team • 10/30/2020
This vulnerability resides within the Hyper-V RemoteFX vGPU implementation on Windows Server systems, representing a critical remote code execution flaw that can be exploited by authenticated attackers within guest operating systems. The vulnerability stems from insufficient input validation mechanisms within the vGPU subsystem that handles communication between host and guest environments. When a malicious user executes code within a guest operating system that utilizes Hyper-V RemoteFX vGPU functionality, the host server fails to properly sanitize or validate the input parameters being transmitted through the vGPU interface. This validation failure creates a pathway for arbitrary code execution on the host system, effectively allowing guest users to escalate their privileges and gain unauthorized control over the underlying physical hardware. The flaw specifically affects systems running Windows Server 2016 and Windows Server 2019 where Hyper-V RemoteFX vGPU is enabled and configured for use with virtual machines.
The technical implementation of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios. These classifications indicate that the input validation failure likely involves improper bounds checking or memory management within the vGPU communication channels, where untrusted input from guest systems is directly processed without adequate sanitization. Attackers can leverage this vulnerability by crafting malicious input sequences that exploit memory corruption patterns within the host's vGPU handling code, potentially leading to complete system compromise. The vulnerability exists in the hypervisor layer where the RemoteFX vGPU functionality operates, making it particularly dangerous as it bypasses traditional guest operating system security boundaries and directly targets the host system's kernel components. This represents a classic example of a privilege escalation vulnerability that allows unprivileged guest users to execute code with host-level privileges.
The operational impact of this vulnerability extends beyond simple remote code execution, as it fundamentally undermines the security isolation that virtualization environments are designed to provide. When successfully exploited, attackers can gain complete control over the host server, potentially leading to data breaches, service disruption, and further lateral movement within the network infrastructure. The vulnerability affects organizations that utilize virtual desktop infrastructure or cloud computing environments where Hyper-V RemoteFX vGPU is enabled, particularly impacting enterprise environments where multiple users share virtualized resources. Organizations running Windows Server 2016 and Windows Server 2019 with vGPU-enabled virtual machines are at risk, with the attack vector requiring only authenticated access to a guest operating system. This makes the vulnerability particularly concerning for environments where guest access is more permissive or where guest users have legitimate administrative capabilities within their virtual machines.
Mitigation strategies should focus on immediate patch deployment through Microsoft's security updates, which address the specific validation flaws in the Hyper-V RemoteFX vGPU implementation. Organizations should implement network segmentation to limit access to vGPU-enabled systems and consider disabling RemoteFX vGPU functionality when it is not required for business operations. The implementation of principle of least privilege should be enforced, ensuring that guest operating systems have minimal necessary access rights to prevent exploitation of this vulnerability. Additionally, monitoring systems should be configured to detect unusual activity patterns that might indicate exploitation attempts, particularly around vGPU communication channels. Organizations should also consider implementing micro-segmentation strategies and network access controls to limit potential lateral movement if exploitation occurs. According to ATT&CK framework, this vulnerability maps to T1059 (Command and Scripting Interpreter) and T1068 (Exploitation for Privilege Escalation) techniques, highlighting the need for comprehensive endpoint detection and response capabilities. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and the inherent risks associated with virtualization technologies when proper isolation mechanisms fail.