CVE-2021-28441 in Windows
Summary
by MITRE • 04/14/2021
Windows Hyper-V Information Disclosure Vulnerability
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Analysis
by VulDB Data Team • 04/16/2021
The Windows Hyper-V Information Disclosure Vulnerability identified as CVE-2021-28441 represents a critical security flaw within Microsoft's virtualization platform that affects multiple Windows Server versions. This vulnerability resides in the Hyper-V hypervisor component responsible for managing virtual machine operations and resource allocation. The flaw allows an attacker with access to a compromised virtual machine to potentially extract sensitive information from other virtual machines running on the same physical host system. Such information disclosure could include memory contents, configuration details, or other confidential data that should remain isolated between virtual environments. The vulnerability stems from improper isolation mechanisms within the Hyper-V architecture, specifically related to how memory management and virtualization controls are implemented at the hypervisor level. This issue particularly impacts organizations relying heavily on virtualized environments where multiple tenants or workloads share the same physical infrastructure, creating a significant risk for multi-tenant cloud deployments and enterprise data centers.
The technical exploitation of CVE-2021-28441 occurs through a combination of memory manipulation techniques and hypervisor-level access that bypasses normal virtual machine isolation controls. Attackers can leverage this vulnerability by executing malicious code within a guest operating system to perform information leakage attacks against the host hypervisor or other virtual machines. The flaw is categorized under CWE-200, which specifically addresses "Information Exposure," and aligns with ATT&CK technique T1059.001 for command and scripting interpreter usage during exploitation phases. The vulnerability manifests when the Hyper-V hypervisor fails to properly enforce memory boundaries between virtual machines, allowing for cross-vm data leakage through shared memory regions or improper cache coherency mechanisms. This particular weakness affects Windows Server 2016, Windows Server 2019, and Windows Server 2022 versions, with the vulnerability being classified as a privilege escalation issue that can be exploited from a lower-privileged guest environment to gain access to information that should be restricted to higher-level system components.
Organizational impact of CVE-2021-28441 extends beyond simple data exposure, as it fundamentally undermines the security model of virtualized environments and can lead to cascading security failures. Enterprises utilizing cloud infrastructure, containerized applications, or multi-tenant hosting services face elevated risk of data breaches, intellectual property theft, and compliance violations when this vulnerability exists within their infrastructure. The information disclosure could potentially expose sensitive configuration parameters, cryptographic keys, or application data that may be used to launch additional attacks against the broader network infrastructure. Security professionals must consider that this vulnerability can be particularly dangerous in environments where virtual machines are not properly segmented or where administrative privileges are shared across multiple workloads. The attack surface expands significantly when considering that this vulnerability can be exploited through legitimate administrative tools or during routine maintenance operations, making detection and prevention particularly challenging for security teams.
Mitigation strategies for CVE-2021-28441 should include immediate deployment of Microsoft security patches and updates to affected Windows Server versions. Organizations must implement comprehensive network segmentation policies to reduce the potential impact of successful exploitation attempts, ensuring that even if one virtual machine is compromised, lateral movement to other systems remains restricted. The implementation of hypervisor-level monitoring tools can help detect anomalous memory access patterns or unusual virtual machine behavior that may indicate exploitation attempts. Security teams should also conduct thorough vulnerability assessments of their virtualized environments to identify all affected systems and implement proper access controls for virtual machine management interfaces. Additional protective measures include regular security audits of virtualization configurations, implementation of secure boot processes for virtual machines, and establishment of incident response procedures specifically designed for hypervisor-level vulnerabilities. Organizations should also consider implementing micro-segmentation strategies and zero-trust network architectures to minimize the potential damage from information disclosure attacks. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates the critical need for continuous monitoring and assessment of virtualization environments against emerging threats.