CVE-2019-0848 in Windows
Summary
by MITRE
An information disclosure vulnerability exists when the win32k component improperly provides kernel information, aka 'Win32k Information Disclosure Vulnerability'. This CVE ID is unique from CVE-2019-0814.
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Analysis
by VulDB Data Team • 07/12/2024
The win32k information disclosure vulnerability represents a critical security flaw within the Windows kernel subsystem that affects the win32k.sys driver component. This vulnerability specifically resides in the Windows kernel-mode driver responsible for managing user-mode graphics operations and window management functions. The flaw manifests when the win32k component fails to properly sanitize kernel memory information before exposing it to user-mode applications, creating an information disclosure vector that can be exploited by malicious actors. This vulnerability is particularly concerning because it operates at the kernel level where privileged operations occur, making it a prime target for advanced persistent threat actors seeking to escalate privileges or gather sensitive system information.
The technical implementation of this vulnerability stems from improper handling of kernel memory structures within the win32k.sys driver during certain graphics and window management operations. When user-mode applications interact with graphics functions, the win32k component processes these requests and may inadvertently leak kernel memory addresses, system structures, or other sensitive information through improperly controlled data flows. This information leakage occurs due to insufficient validation and sanitization of kernel data before it is returned to user-mode processes, creating a pathway for attackers to extract valuable information about the kernel memory layout, system configuration, or other internal operational details. The vulnerability is classified under CWE-200, which deals with information exposure, and specifically relates to improper information handling within kernel-mode drivers.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with crucial intelligence for crafting more sophisticated attacks. An attacker who successfully exploits this vulnerability can obtain kernel memory addresses, system structure layouts, and other sensitive data that significantly reduces the difficulty of subsequent exploitation attempts. This information can be leveraged to bypass security mechanisms such as address space layout randomization, kernel address space layout randomization, and other exploit mitigations. The vulnerability affects various Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it a widespread concern across enterprise environments. According to ATT&CK framework, this vulnerability maps to T1068, which covers 'Exploitation for Privilege Escalation', and T1082, which involves 'System Information Discovery', as the leaked information directly enables further reconnaissance activities.
Mitigation strategies for this vulnerability primarily focus on immediate patching and system hardening measures. Microsoft released security updates that address the information disclosure issue by implementing proper kernel memory sanitization within the win32k component. Organizations should prioritize applying the relevant security patches as soon as possible, particularly for systems running affected Windows versions. Additional protective measures include implementing application whitelisting to limit user-mode application access to graphics functions, enabling exploit protection mechanisms, and monitoring for suspicious kernel memory access patterns. Network segmentation and privilege separation can also help reduce the potential impact if an attacker were to exploit this vulnerability. Security teams should also consider deploying behavioral monitoring solutions that can detect anomalous kernel memory access patterns or information disclosure attempts, as these activities may indicate exploitation attempts. The vulnerability demonstrates the critical importance of kernel-mode security and the need for comprehensive security testing of system drivers, particularly those handling user input and graphics operations.