CVE-2021-34500 in Windows
Summary
by MITRE • 07/15/2021
Windows Kernel Memory Information Disclosure Vulnerability
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Analysis
by VulDB Data Team • 07/17/2021
This vulnerability resides within the Windows kernel's memory management subsystem and represents a critical information disclosure flaw that allows attackers to extract sensitive kernel memory contents through crafted system calls. The vulnerability stems from improper validation of memory access parameters during kernel operations, specifically affecting how the operating system handles memory information retrieval requests. Attackers can exploit this weakness by constructing malicious kernel API calls that bypass normal memory access controls, potentially exposing kernel data structures, sensitive variables, and other confidential information stored in kernel memory space. The flaw exists in the kernel's memory information disclosure mechanisms and affects multiple Windows versions including windows 10, windows server 2016, and windows server 2019.
The technical implementation of this vulnerability involves manipulating kernel memory access controls through specific API calls that should normally be restricted to privileged system components. When a user-mode application or driver makes a request to retrieve kernel memory information, the kernel fails to properly validate the requesting entity's privileges or the legitimacy of the requested memory range. This validation failure creates an opportunity for attackers to access memory locations that should remain protected, potentially exposing sensitive kernel data including security credentials, cryptographic keys, or system configuration information. The vulnerability is classified as a memory disclosure issue and maps to common weakness enumeration CWE-200, which specifically addresses improper information exposure.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked kernel memory information can provide attackers with critical system insights that enable more sophisticated attacks. Once an attacker gains access to kernel memory contents, they can potentially extract security tokens, process credentials, or other sensitive data that could be used for privilege escalation or lateral movement within the network. The vulnerability can be exploited through local attacks where an attacker already has some level of system access, making it particularly dangerous in environments where attackers have achieved initial compromise through other means. This type of vulnerability aligns with attack techniques documented in the attack tree framework under the information gathering category, specifically targeting system memory for reconnaissance purposes.
Mitigation strategies for this vulnerability require immediate implementation of microsoft security updates that address the kernel memory validation issues. System administrators should prioritize patching affected systems, particularly those running windows 10, windows server 2016, and windows server 2019 versions. Additional protective measures include implementing kernel-mode exploit prevention techniques such as address space layout randomization, kernel address space layout randomization, and enabling exploit protection features within windows defender. Organizations should also consider implementing network segmentation and access controls to limit potential attack vectors and reduce the impact of successful exploitation attempts. Regular security monitoring and log analysis should be enhanced to detect anomalous kernel memory access patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of maintaining robust kernel security controls and proper privilege validation mechanisms that are essential for protecting system integrity and confidentiality.