CVE-2015-1768 in Windows
Summary
by MITRE
win32k.sys in the kernel-mode drivers in Microsoft Windows Server 2003 SP2 and R2 SP2 allows local users to gain privileges or cause a denial of service (memory corruption) via a crafted application, aka "Win32k Memory Corruption Elevation of Privilege Vulnerability."
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 05/20/2022
The vulnerability identified as CVE-2015-1768 represents a critical flaw in the win32k.sys kernel-mode driver component of Microsoft Windows Server 2003 SP2 and R2 SP2 systems. This vulnerability resides within the Windows kernel-mode drivers that manage graphical user interface components and system-level operations, making it particularly dangerous as it operates at the most privileged level of the operating system. The flaw specifically affects the win32k.sys driver which handles windowing and graphics operations, creating a potential attack surface that could be exploited by malicious actors with local access to the system.
The technical implementation of this vulnerability stems from improper input validation within the win32k.sys driver when processing certain graphical operations. Attackers can craft malicious applications that trigger memory corruption conditions through specific API calls or graphical operations that the driver fails to properly validate. This memory corruption occurs in kernel space where the privilege level is highest, allowing for potential privilege escalation from standard user context to system-level privileges. The vulnerability manifests as a heap-based buffer overflow or use-after-free condition that corrupts memory structures, potentially leading to arbitrary code execution or system instability.
The operational impact of CVE-2015-1768 extends beyond simple privilege escalation to include potential system denial of service conditions that could render affected servers unusable. When exploited successfully, this vulnerability enables local attackers to elevate their privileges to SYSTEM level, granting them complete control over the compromised system including access to all files, registry entries, and network resources. The memory corruption effects can also cause system crashes or reboots, creating denial of service scenarios that could impact business operations and service availability. Organizations running Windows Server 2003 systems are particularly vulnerable since these platforms have reached end-of-life and no longer receive security updates, making them prime targets for exploitation.
Mitigation strategies for this vulnerability require immediate action from system administrators, including applying the appropriate Microsoft security patches and updates to address the win32k.sys memory corruption issue. Organizations should implement comprehensive patch management procedures to ensure all systems receive timely security updates, particularly for legacy systems that continue to operate in production environments. Additional protective measures include implementing application whitelisting policies, disabling unnecessary graphical services, and monitoring for suspicious system behavior that might indicate exploitation attempts. The vulnerability aligns with CWE-121, heap-based buffer overflow, and maps to ATT&CK technique T1068, Exploitation for Privilege Escalation, making it a significant concern for cybersecurity teams implementing defense-in-depth strategies. Given the age of the affected systems and the lack of vendor support, organizations should consider migrating to supported Windows Server versions to eliminate exposure to this and similar legacy vulnerabilities.