CVE-2020-0717 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-2020-0716.
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Analysis
by VulDB Data Team • 03/29/2024
The win32k information disclosure vulnerability represents a critical security flaw within the Windows kernel subsystem that affects the win32k.sys driver component. This vulnerability stems from improper handling of kernel information within the graphics subsystem, specifically when processing user-mode requests that interact with kernel-mode components. The flaw allows attackers to extract sensitive kernel memory contents through crafted input sequences that bypass normal access controls and privilege boundaries. The vulnerability is particularly concerning because it operates at the kernel level where system integrity and security controls are most critical, making it a prime target for exploitation by advanced persistent threats.
The technical implementation of this vulnerability involves the win32k.sys driver's inadequate validation of input parameters when processing graphics-related system calls. When user-mode applications submit specific requests to the graphics subsystem, the win32k component fails to properly sanitize or validate the data before exposing kernel memory addresses or other sensitive information. This improper information handling creates a pathway for attackers to perform information disclosure attacks that can reveal kernel memory layout details, security keys, or other confidential data structures. The vulnerability is classified under CWE-200, which specifically addresses "Information Exposure" and represents a fundamental breakdown in the principle of least privilege within the Windows security model. The flaw demonstrates a classic case of insufficient input validation and improper error handling in kernel-mode code, where the component fails to properly enforce access control boundaries.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can serve as a precursor to more sophisticated attacks within the Windows security architecture. Attackers can leverage the exposed kernel information to craft more effective exploitation techniques, including bypassing exploit mitigations like address space layout randomization and kernel address space layout randomization. The vulnerability affects multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it a widespread concern across enterprise environments. Security researchers have documented how this information disclosure can be combined with other vulnerabilities to achieve privilege escalation and complete system compromise, particularly in targeted attacks against high-value targets. The vulnerability's impact is further amplified by its potential to be exploited in zero-day attacks where defenders have no prior knowledge of the specific flaw.
Mitigation strategies for this vulnerability focus on both immediate patching and operational security measures to reduce attack surface exposure. Microsoft released security updates that address the information disclosure by implementing proper input validation and memory access controls within the win32k.sys driver. Organizations should prioritize immediate deployment of these patches across all affected systems, particularly in environments where privileged accounts or sensitive data are present. Additional mitigations include implementing enhanced monitoring for suspicious system calls and memory access patterns that could indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1059 which covers command and scripting interpreter, as attackers may use the disclosed information to craft more effective payloads. Network segmentation and privilege reduction measures can help limit the potential impact of successful exploitation, while security solutions should be configured to detect anomalous behavior in graphics subsystem calls that could indicate exploitation attempts. The vulnerability also highlights the importance of kernel-mode exploit mitigation strategies and proper security architecture design principles.