CVE-2020-0691 in Windows
Summary
by MITRE
An elevation of privilege vulnerability exists in Windows when the Windows kernel-mode driver fails to properly handle objects in memory, aka 'Win32k Elevation of Privilege Vulnerability'. This CVE ID is unique from CVE-2020-0719, CVE-2020-0720, CVE-2020-0721, CVE-2020-0722, CVE-2020-0723, CVE-2020-0724, CVE-2020-0725, CVE-2020-0726, CVE-2020-0731.
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Analysis
by VulDB Data Team • 03/29/2024
The vulnerability identified as CVE-2020-0691 represents a critical elevation of privilege flaw within the Windows operating system that resides in the Windows kernel-mode driver component. This weakness specifically affects the win32k.sys driver which serves as the foundation for Windows graphical user interface operations including window management, input handling, and display functions. The vulnerability stems from improper handling of objects in memory, creating a pathway for malicious actors to escalate their privileges from standard user level to SYSTEM level access. The affected driver operates at the highest privilege level within the Windows kernel, making this flaw particularly dangerous as it directly impacts the system's core security architecture.
The technical implementation of this vulnerability involves the Windows kernel-mode driver's failure to properly validate or manage memory objects during specific operations within the win32k.sys component. This flaw allows an attacker to manipulate memory structures in ways that bypass normal security checks and access controls. The vulnerability is categorized under CWE-121 as a buffer overflow condition, where insufficient memory management leads to unauthorized privilege escalation. The flaw specifically manifests when the kernel driver processes certain graphical objects or handles user input through the Windows graphical subsystem, creating opportunities for memory corruption that can be exploited to execute arbitrary code with elevated privileges. This type of vulnerability is classified as a kernel-mode privilege escalation, placing it within the ATT&CK framework under T1068 (Exploitation for Privilege Escalation) and T1547.001 (Registry Run Keys/Startup Folder).
The operational impact of CVE-2020-0691 is severe and far-reaching across enterprise environments, as successful exploitation grants attackers complete system control without requiring any additional authentication or prior access. Once an attacker achieves privilege escalation, they can access all system resources, modify critical files, install malicious software, establish persistence mechanisms, and potentially move laterally within network environments. The vulnerability affects multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it particularly concerning for organizations with diverse operating system deployments. The exploitation typically requires local user access or a previous foothold in the system, but the resulting privilege escalation provides attackers with unrestricted access to the entire system, including protected registry keys, system files, and network resources.
Mitigation strategies for this vulnerability should prioritize immediate patch deployment through Microsoft's regular security updates, as the vendor has released patches specifically addressing this flaw in the Windows security updates. Organizations should implement comprehensive monitoring for suspicious privilege escalation activities and anomalous system behavior that might indicate exploitation attempts. Network segmentation and least privilege access controls can help limit the potential damage if exploitation occurs, while endpoint detection and response solutions should be configured to monitor for kernel-mode activity and memory manipulation patterns. System administrators should also consider implementing additional security measures such as Windows Defender Application Control, exploit protection policies, and disabling unnecessary graphical services where possible. The vulnerability's nature as a kernel-mode flaw makes traditional user-level security measures insufficient, requiring system-level interventions and comprehensive patch management protocols to ensure complete remediation. Organizations should also conduct thorough vulnerability assessments to identify systems potentially vulnerable to this and related CVEs, particularly focusing on the Win32k.sys driver components and their associated graphical subsystem operations.