CVE-2015-2381 in Windows
Summary
by MITRE
win32k.sys in the kernel-mode drivers in Microsoft Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 allows local users to obtain sensitive information from kernel memory via a crafted application, aka "Win32k Information Disclosure Vulnerability," a different vulnerability than CVE-2015-2382.
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Analysis
by VulDB Data Team • 05/31/2022
The vulnerability identified as CVE-2015-2381 represents a critical information disclosure flaw within the win32k.sys kernel-mode driver component of Microsoft Windows operating systems. This vulnerability affects Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 systems, making it a widespread concern across multiple Windows versions. The flaw resides in the kernel-mode drivers that handle graphical user interface operations, specifically within the win32k.sys file which manages windowing system functionality including user interface elements and graphics rendering operations. The vulnerability stems from improper handling of certain kernel memory operations that allow unauthorized access to sensitive information stored in kernel memory space.
The technical nature of this vulnerability involves a local privilege escalation scenario where a crafted application can exploit memory access patterns to extract sensitive data from kernel memory regions. This type of flaw typically occurs when the kernel-mode driver fails to properly validate input parameters or when it performs operations that leave memory in an exploitable state. The vulnerability is classified as a kernel information disclosure issue that operates at the most privileged level of the operating system, making it particularly dangerous for attackers who can leverage it to gain insights into system memory structures and potentially identify other vulnerabilities. According to CWE classification, this vulnerability aligns with CWE-200, which deals with exposure of sensitive information, and specifically relates to improper access control mechanisms in kernel-mode components. The attack vector requires local execution capability, meaning an attacker must already have a foothold on the system to exploit this vulnerability, but the impact can be severe as it provides access to kernel memory that may contain credentials, encryption keys, or other sensitive system information.
The operational impact of CVE-2015-2381 extends beyond simple information disclosure, as it can serve as a stepping stone for more sophisticated attacks within the Windows environment. When an attacker successfully exploits this vulnerability, they gain access to kernel memory that may contain sensitive data structures, process information, or memory addresses that could be used to bypass security mechanisms or develop additional exploits. This vulnerability is particularly concerning in enterprise environments where Windows systems may be running with elevated privileges or where sensitive data is processed in kernel space. The fact that this vulnerability operates at the kernel level means that traditional user-mode security controls may be insufficient to prevent exploitation, and the impact affects the fundamental integrity of the operating system's security model. The vulnerability's relationship to CVE-2015-2382 demonstrates that Microsoft was aware of multiple related issues within the same kernel driver component, suggesting a broader architectural weakness in the win32k.sys implementation. From an ATT&CK framework perspective, this vulnerability would map to techniques involving privilege escalation and credential access, specifically targeting the kernel to gain elevated system privileges and access to sensitive information that could be used for further compromise of the system or network.
Mitigation strategies for CVE-2015-2381 primarily involve applying Microsoft security updates and patches as released through the Windows Update mechanism or Microsoft Security Response Center. Organizations should prioritize patch deployment across all affected Windows versions, particularly in environments where local access might be compromised or where the systems handle sensitive information. System administrators should also implement monitoring solutions to detect unauthorized local execution of potentially malicious applications that might attempt to exploit this vulnerability. Additional defensive measures include implementing application whitelisting policies to prevent unauthorized code execution, conducting regular security assessments of kernel-mode components, and maintaining up-to-date intrusion detection systems that can identify suspicious memory access patterns. The vulnerability highlights the importance of kernel-mode security hardening practices and proper input validation in system drivers, as well as the need for continuous security testing of core operating system components. Organizations should also consider implementing network segmentation and privilege separation to limit the potential impact of successful exploitation, as even if an attacker gains kernel-level access, they may be constrained by network security controls and access controls implemented at higher levels of the system architecture.