CVE-2015-2363 in Windows
Summary
by MITRE
win32k.sys in the kernel-mode drivers in Microsoft Windows Server 2003 SP2 and R2 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012, and Windows RT allows local users to gain privileges via a crafted application, aka "Win32k Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 05/31/2022
The CVE-2015-2363 vulnerability represents a critical privilege escalation flaw within the Windows kernel-mode driver component win32k.sys. This vulnerability affects multiple versions of Microsoft Windows operating systems including server and client editions across various service pack configurations. The flaw resides in the Windows graphical subsystem responsible for handling user interface elements and window management operations. Attackers can exploit this vulnerability through a crafted application that leverages the inherent weaknesses in the kernel-mode driver execution environment. The vulnerability specifically targets the win32k.sys driver which manages the graphical user interface components including windowing, graphics rendering, and user input handling mechanisms that operate at the highest privilege level within the Windows operating system architecture.
The technical exploitation of CVE-2015-2363 occurs when a malicious application triggers a specific code path within win32k.sys that fails to properly validate input parameters or maintain proper access controls during kernel-mode operations. This flaw allows local attackers who already have user-level access to execute arbitrary code with kernel-level privileges, effectively bypassing the operating system's security boundaries. The vulnerability typically manifests through improper handling of user-mode to kernel-mode transitions where input validation is insufficient to prevent malicious data from corrupting kernel memory structures or manipulating privilege escalation mechanisms. The exploitation process often involves leveraging race conditions or buffer overflow conditions within the graphics subsystem that can be triggered through carefully crafted window management operations or graphics rendering commands.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete control over the affected system. Once successfully exploited, adversaries can install malware, modify system files, create new user accounts, disable security features, and establish persistent access to the compromised machine. The vulnerability's presence in widely deployed operating systems including Windows Server 2003 and Windows Vista makes it particularly dangerous as it affects legacy systems that may not receive regular security updates. Organizations running these affected systems face significant risk of system compromise, data breaches, and potential lateral movement within network environments where these vulnerable systems exist. The local nature of the attack means that attackers do not require network connectivity or remote access capabilities to exploit the vulnerability, making it particularly challenging to defend against in environments where user access is not strictly controlled.
Security mitigations for CVE-2015-2363 primarily focus on applying the Microsoft security patches released in the May 2015 security updates. Organizations should prioritize immediate deployment of the relevant security updates across all affected systems, particularly those running older operating systems like Windows Server 2003 and Windows Vista that may not receive extended support. Additional defensive measures include implementing strict user access controls, disabling unnecessary graphical features, and monitoring for suspicious process behavior that might indicate exploitation attempts. The vulnerability aligns with CWE-119 which describes weaknesses in memory management and improper handling of memory access violations within kernel-mode drivers. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques under the T1068 category, specifically targeting kernel-mode privilege escalation methods. Network segmentation and application whitelisting can provide additional layers of defense, though the local nature of the attack means these measures are secondary to proper patch management and system hardening practices.