CVE-2020-1152 in Windows
Summary
by MITRE
<p>An elevation of privilege vulnerability exists when Windows improperly handles calls to Win32k.sys. An attacker who successfully exploited the vulnerability could gain elevated privileges on a targeted system.</p> <p>To exploit the vulnerability, an attacker would have to log on to an affected system and run a specially crafted script or application.</p> <p>The update addresses the vulnerability by correcting how Windows handles calls to Win32k.</p>
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Analysis
by VulDB Data Team • 02/24/2026
The vulnerability identified as CVE-2020-1152 represents a critical elevation of privilege flaw within the Windows operating system that specifically targets the Win32k.sys kernel driver. This vulnerability falls under the Common Weakness Enumeration category CWE-264, which encompasses permissions, privileges, and access control issues. The flaw manifests when Windows improperly processes certain calls to the Win32k.sys component, which serves as the kernel-mode driver responsible for Windows graphical user interface operations including window management, input handling, and graphics rendering. The vulnerability exists in the kernel-mode execution context, making it particularly dangerous as successful exploitation can result in complete system compromise. Attackers can leverage this weakness to escalate their privileges from standard user level to system level, effectively gaining unrestricted access to all system resources and data.
The exploitation vector for CVE-2020-1152 requires an attacker to first establish a foothold on the target system through legitimate user authentication, as the vulnerability cannot be exploited remotely without prior access. Once authenticated, the attacker must execute a specially crafted script or application that triggers the malformed Win32k.sys call sequence. This execution typically involves leveraging the kernel-mode vulnerability through user-mode applications that can manipulate the graphics subsystem or windowing APIs. The attack chain often follows the pattern of initial compromise followed by privilege escalation, where the attacker crafts malicious code that interacts with the vulnerable kernel driver through legitimate Windows API calls that ultimately lead to privilege elevation. The attack is classified under the MITRE ATT&CK framework as privilege escalation technique, specifically targeting kernel-mode vulnerabilities to gain SYSTEM-level access.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with the foundation for complete system compromise and persistent access. When successfully exploited, the vulnerability allows attackers to bypass standard Windows security controls including user access control, integrity levels, and security policies that normally protect system resources. The affected system becomes vulnerable to further attacks including data exfiltration, lateral movement, and installation of additional malware. The vulnerability affects multiple Windows versions including Windows 10, Windows Server 2016, and Windows Server 2019, making it a widespread concern for enterprise environments. Organizations running these operating systems face significant risk if the vulnerability remains unpatched, as it enables attackers to establish persistent backdoors and maintain long-term access to compromised systems.
Microsoft addressed this vulnerability through a security update that modifies how Windows handles calls to the Win32k.sys driver, effectively patching the kernel-mode flaw that allowed privilege escalation. The fix involves strengthening input validation and proper handling of kernel-mode API calls that previously allowed attackers to manipulate the graphics subsystem in ways that could lead to privilege escalation. System administrators should prioritize deployment of this security update across all affected Windows systems, particularly those running server versions or systems with elevated privileges. The mitigation strategy should include comprehensive vulnerability management programs that regularly assess and remediate kernel-mode vulnerabilities. Organizations should also implement additional security controls such as application whitelisting, user account control monitoring, and behavioral analytics to detect anomalous privilege escalation attempts that might indicate exploitation of similar vulnerabilities. The vulnerability serves as a reminder of the critical importance of kernel security and the need for continuous monitoring of system integrity to prevent exploitation of low-level operating system flaws.