CVE-2020-0876 in Windows
Summary
by MITRE
An information disclosure vulnerability exists when the win32k component improperly provides kernel information, aka 'Win32k Information Disclosure Vulnerability'.
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Analysis
by VulDB Data Team • 04/11/2024
The CVE-2020-0876 vulnerability represents a critical information disclosure flaw within the Windows kernel subsystem, specifically affecting the win32k.sys component that manages user-mode graphics operations and window management functions. This vulnerability arises from improper handling of kernel memory structures and object references within the graphics subsystem, creating an avenue for unauthorized information disclosure that could be exploited by malicious actors to gain insights into kernel memory layouts and system internals.
The technical exploitation of this vulnerability occurs through the manipulation of graphics-related APIs and kernel object handles that are processed by the win32k.sys driver. When legitimate user-mode applications interact with graphics operations, the kernel component fails to properly validate or sanitize memory references, potentially allowing attackers to extract kernel memory addresses, object type information, or other sensitive kernel data structures. This information disclosure can be leveraged to bypass security mitigations such as address space layout randomization and kernel address space layout randomization, which rely on the unpredictability of memory locations.
From an operational impact perspective, this vulnerability poses significant risks to system security and stability. Attackers who successfully exploit this information disclosure could use the gathered kernel information to craft more sophisticated attacks, including privilege escalation attempts or targeted exploitation of other vulnerabilities. The vulnerability affects Windows 10 versions and Windows Server 2019, making it particularly concerning for enterprise environments where these operating systems are prevalent. The flaw is categorized under CWE-200, which specifically addresses information exposure vulnerabilities, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation.
Security researchers have noted that this vulnerability can be triggered through various user-mode applications that utilize graphics APIs, particularly those involving window management or graphics rendering operations. The exploitation typically requires an attacker to have a foothold on the target system, as the vulnerability itself is not directly exploitable from network-based attacks. However, once achieved, the information disclosure can serve as a critical stepping stone for more advanced attacks. Microsoft has addressed this vulnerability through security updates that improve memory validation and object reference handling within the win32k.sys component, emphasizing the importance of timely patch management for maintaining system security.
The vulnerability demonstrates the inherent complexity of kernel-mode security and the challenges of protecting system internals from information leakage through seemingly benign user-mode operations. Organizations should prioritize immediate patch deployment and implement monitoring solutions to detect potential exploitation attempts. The flaw also highlights the importance of maintaining up-to-date security patches and understanding the attack surface presented by graphics subsystems, which often have complex interactions with kernel memory management and object handling mechanisms.