CVE-2025-21335 in Windows
Summary
by MITRE • 01/14/2025
Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability
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Analysis
by VulDB Data Team • 01/16/2025
This vulnerability resides within the Windows Hyper-V NT Kernel Integration Virtual Switch Provider component, representing a critical elevation of privilege flaw that affects systems running Hyper-V virtualization environments. The issue stems from improper validation of input parameters within the kernel-mode driver responsible for handling virtual switch operations. Attackers can exploit this weakness by crafting malicious input that bypasses expected security checks, ultimately allowing unauthorized code execution with kernel-level privileges. The vulnerability specifically impacts the VSP integration layer that facilitates communication between virtual machines and the underlying host system, creating a pathway for privilege escalation attacks that can compromise the entire virtualization infrastructure.
The technical implementation of this vulnerability demonstrates a classic kernel-mode memory corruption issue that occurs when processing network packet data through the Hyper-V virtual switch provider. The flaw manifests when the kernel driver fails to properly validate the size and structure of incoming data packets, enabling attackers to manipulate memory layout and execute arbitrary code with SYSTEM privileges. This type of vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which addresses heap-based buffer overflow scenarios. The vulnerability operates at the kernel level, making it particularly dangerous as it can bypass standard user-mode security controls and directly manipulate system resources.
From an operational impact perspective, this vulnerability presents significant risk to enterprise environments that rely heavily on Hyper-V virtualization for their infrastructure. Organizations running multiple virtual machines on affected systems face potential compromise of their entire virtualized environment, as successful exploitation could allow attackers to access all virtual machines hosted on the same physical system. The attack surface extends beyond individual VMs to include the host system itself, potentially enabling lateral movement across the network and access to sensitive data stored within the virtualized environment. This vulnerability directly maps to ATT&CK technique T1055, which covers privilege escalation through kernel exploits, and T1071, which addresses application layer protocol usage for command and control communications.
Mitigation strategies for this vulnerability should prioritize immediate patch deployment from Microsoft, as the company has released security updates addressing the specific kernel-mode validation issues. Organizations should also implement network segmentation to limit access to Hyper-V management interfaces and consider disabling unnecessary virtual switch features that may increase the attack surface. Additional defensive measures include monitoring for unusual network traffic patterns that might indicate exploitation attempts, implementing kernel-mode protection mechanisms, and conducting regular vulnerability assessments of virtualization environments. System administrators should also review and restrict administrative privileges assigned to virtual machine users, ensuring that only authorized personnel have access to critical virtualization management functions. The vulnerability requires immediate attention due to its potential for widespread impact across enterprise virtualization deployments and the relatively low complexity required for successful exploitation.