CVE-2017-8687 in Windows
Summary
by MITRE
The Windows kernel component on Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016 allows an information disclosure vulnerability when it improperly handles objects in memory, aka "Win32k Information Disclosure Vulnerability". This CVE ID is unique from CVE-2017-8678, CVE-2017-8680, CVE-2017-8677, and CVE-2017-8681.
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Analysis
by VulDB Data Team • 10/07/2024
The Windows kernel component vulnerability identified as CVE-2017-8687 represents a critical information disclosure flaw within the win32k.sys driver that governs user interface rendering and window management operations in Microsoft Windows operating systems. This vulnerability specifically affects a wide range of Microsoft products including Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 versions 1511, 1607, and 1703, as well as Windows Server 2016. The flaw stems from improper handling of objects in memory, creating a scenario where malicious actors can potentially extract sensitive information from the kernel memory space. This vulnerability operates at the kernel level, making it particularly dangerous as it can bypass standard user-mode protections and access privileged system resources. The affected win32k.sys driver is responsible for managing graphics rendering, window management, and user interface components, making it a prime target for exploitation due to its critical role in system operation.
The technical implementation of this information disclosure vulnerability occurs when the win32k.sys driver fails to properly validate or handle certain memory objects during user interface operations. This improper memory handling allows attackers to craft specific input sequences or trigger conditions that cause the kernel to expose sensitive data structures or memory contents that should remain protected. The vulnerability manifests through the kernel's insufficient validation mechanisms when processing user-mode requests that interact with graphical objects, leading to potential information leakage that could include system memory contents, kernel pointers, or other sensitive operational data. This type of vulnerability falls under the Common Weakness Enumeration category CWE-20, which describes "Improper Input Validation" as the underlying weakness, though specifically in kernel memory management contexts. The exploitation requires a user to interact with the vulnerable system, typically through a malicious application or document that triggers the flawed memory handling routine.
The operational impact of CVE-2017-8687 extends beyond simple information disclosure, as the leaked kernel memory information can provide attackers with critical insights into system internals that could facilitate further exploitation attempts. An attacker who successfully exploits this vulnerability could potentially obtain kernel pointers, memory layout information, or other sensitive data that would aid in bypassing security mitigations like ASLR (Address Space Layout Randomization) or DEP (Data Execution Prevention). This information leakage creates a significant risk for advanced persistent threat actors who might use the acquired data to plan more sophisticated attacks, such as kernel exploits or privilege escalation techniques. The vulnerability's presence across multiple Windows versions means that organizations with legacy systems are particularly at risk, as these systems often lack modern security mitigations or may be difficult to patch due to compatibility concerns.
Mitigation strategies for CVE-2017-8687 primarily focus on applying Microsoft security updates and implementing additional security controls to reduce the attack surface. Organizations should prioritize installing the relevant security patches released by Microsoft, which address the improper memory handling in the win32k.sys driver. Beyond patching, system administrators should implement additional security measures such as disabling unnecessary graphical features, restricting user privileges, and monitoring for unusual memory access patterns that might indicate exploitation attempts. The vulnerability's classification under the ATT&CK framework would place it in the information gathering phase, potentially supporting later stages of attack such as privilege escalation or defense evasion. Network segmentation and application whitelisting can help reduce the risk of exploitation through user interaction vectors, while regular security assessments should monitor for signs of memory corruption or information leakage that could indicate successful exploitation of this vulnerability.