CVE-2025-27735 in Windows
Summary
by MITRE • 04/08/2025
Insufficient verification of data authenticity in Windows Virtualization-Based Security (VBS) Enclave allows an authorized attacker to bypass a security feature locally.
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Analysis
by VulDB Data Team • 04/08/2025
Windows Virtualization-Based Security VBS enclaves represent a critical security mechanism designed to protect sensitive data and code execution within isolated virtual environments. The vulnerability stems from inadequate verification processes that fail to properly authenticate data integrity within these enclave boundaries. This weakness creates a scenario where an authorized attacker with local access can manipulate or bypass the intended security controls that should maintain data confidentiality and integrity. The flaw operates at the core of VBS architecture where trust boundaries are improperly enforced, allowing malicious actors to inject unauthorized code or manipulate protected information without detection.
The technical implementation of this vulnerability manifests through insufficient cryptographic verification mechanisms within the enclave runtime environment. When VBS enclaves process data inputs, they rely on authentication checks that may not adequately validate source authenticity or data integrity. This weakness enables an attacker who already possesses legitimate local credentials to exploit procedural gaps in the verification pipeline, potentially compromising the secure execution environment that should isolate sensitive operations from the host system. The vulnerability essentially undermines the fundamental principle of trusted execution environments where all inputs must be rigorously verified before processing.
From an operational impact perspective, this flaw creates significant risk for organizations relying on VBS for protecting sensitive workloads such as credential storage, cryptographic operations, or confidential computing scenarios. An attacker could potentially extract protected information, inject malicious code into secure processes, or manipulate data flows within the enclave environment. The local nature of the attack means that traditional network-based security controls may not prevent exploitation, making this particularly dangerous in environments where insider threats are a concern. The vulnerability directly impacts the confidentiality and integrity assurances that VBS is designed to provide.
Security professionals should implement comprehensive monitoring solutions to detect anomalous behavior within VBS enclave operations, including unusual data access patterns or unauthorized code injection attempts. Organizations must ensure proper patch management protocols are maintained to address the underlying VBS implementation gaps. Mitigation strategies include enhanced logging and audit capabilities for enclave activities, regular security assessments of virtualized environments, and careful privilege management to minimize local access rights for users who do not require such elevated permissions. The vulnerability aligns with CWE-284 Access Control Issues and relates to ATT&CK technique T1552 Credential Access through exploitation of trusted execution environment weaknesses.
This particular vulnerability demonstrates the complexity inherent in virtualized security implementations where multiple layers of trust must be maintained simultaneously. The flaw represents a failure in the security architecture's principle of least privilege enforcement within isolated environments, potentially allowing attackers to escalate their privileges or access protected data that should remain inaccessible even to authorized users with local system access. Organizations implementing VBS solutions must understand that while these technologies provide strong protection against external threats, internal verification mechanisms require equal attention to prevent exploitation by authorized insiders who may have legitimate access but intent to compromise security controls.