CVE-2021-43244 in Windows
Summary
by MITRE • 12/15/2021
Windows Kernel Information Disclosure Vulnerability
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Analysis
by VulDB Data Team • 10/07/2025
The Windows Kernel Information Disclosure Vulnerability identified as CVE-2021-43244 represents a critical security flaw within the Windows operating system kernel that allows unauthorized information disclosure. This vulnerability resides in the kernel-mode drivers and affects multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019. The flaw stems from improper handling of memory operations within kernel space, creating potential pathways for malicious actors to extract sensitive information from system memory. According to CWE-200, this vulnerability falls under the category of Information Exposure, where the system inadvertently reveals confidential data that should remain protected. The vulnerability is particularly concerning because it operates at the kernel level, where the most privileged system operations occur, making it an attractive target for advanced persistent threats.
The technical implementation of this vulnerability involves a race condition or improper validation within kernel memory management functions. Attackers can exploit this weakness by crafting specific system calls or memory operations that trigger the flawed kernel code path. The vulnerability typically manifests when the kernel processes certain memory access requests without proper validation of input parameters or memory boundaries. This allows attackers to read kernel memory contents that should normally be protected from user-mode applications. The flaw specifically affects how the kernel handles certain memory allocation and deallocation operations, creating opportunities for information leakage through memory dumps or side-channel attacks. The vulnerability can be triggered through various means including malicious drivers, system services, or even legitimate applications that inadvertently invoke the flawed code paths.
The operational impact of CVE-2021-43244 extends beyond simple information disclosure, as the leaked kernel information can serve as a foundation for more sophisticated attacks. An attacker who successfully exploits this vulnerability can potentially obtain sensitive kernel data structures, memory addresses, or other confidential information that could be used to bypass security mitigations such as address space layout randomization or kernel address space layout randomization. This information leakage creates opportunities for privilege escalation attacks and can facilitate the development of more targeted exploits against the system. The vulnerability's impact is particularly severe in enterprise environments where Windows systems are often targeted by advanced threat actors. According to ATT&CK framework technique T1068, this vulnerability could be leveraged for privilege escalation, while technique T1005 indicates potential for data hijacking through information disclosure. Organizations running affected Windows versions face significant risk of system compromise and data breaches.
Mitigation strategies for CVE-2021-43244 should prioritize immediate patch deployment from Microsoft, which addresses the underlying kernel memory handling flaw through updated driver components and kernel functions. System administrators should also implement additional security measures including kernel patch management, regular system updates, and monitoring for anomalous memory access patterns. The vulnerability requires careful attention to kernel driver validation and memory management procedures, as outlined in Microsoft security best practices for kernel-mode security. Network segmentation and access controls should be strengthened to limit potential attack vectors, while security monitoring should focus on detecting unauthorized memory access attempts or unusual system behavior. Organizations should also consider implementing exploit prevention mechanisms such as control flow integrity checks and kernel-mode exploit detection systems. The vulnerability highlights the importance of maintaining up-to-date kernel security patches and implementing comprehensive security monitoring solutions that can detect and respond to kernel-level information disclosure attempts. Regular security assessments and vulnerability scanning should be conducted to identify any potential exploitation attempts or related security weaknesses that could compound the impact of this vulnerability.