CVE-2017-8593 in Windows
Summary
by MITRE
Microsoft Win32k in 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 elevation of privilege vulnerability when it fails to properly handle objects in memory, aka "Win32k Elevation of Privilege Vulnerability".
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Analysis
by VulDB Data Team • 01/07/2021
The CVE-2017-8593 vulnerability represents a critical elevation of privilege flaw within Microsoft Windows operating systems that affects a broad range of platforms 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 Gold, 1511, 1607, and 1703, as well as Windows Server 2016. This vulnerability resides in the Win32k.sys kernel-mode driver which is responsible for handling user interface components and graphics rendering operations. The flaw stems from improper handling of objects in memory, specifically within the windowing subsystem that manages graphical user interface elements and system calls between user applications and the kernel. According to CWE-121, this vulnerability falls under the category of stack-based buffer overflow conditions where insufficient validation occurs when processing objects in memory, creating opportunities for malicious code execution.
The technical implementation of this vulnerability exploits weaknesses in how the Win32k.sys driver manages graphics objects and memory allocation during user interface operations. Attackers can craft specially crafted malicious applications or documents that trigger the vulnerable code path when the system processes graphical elements through the Win32k subsystem. The flaw allows an attacker with limited privileges to escalate their access level from standard user to system-level privileges, effectively bypassing security controls and gaining complete control over the affected system. This type of vulnerability operates at the kernel level where privilege escalation occurs through improper object handling, making it particularly dangerous as it can be exploited without requiring physical access to the target system. The vulnerability aligns with ATT&CK technique T1068 which describes the use of local privilege escalation techniques to gain system-level access through kernel-mode exploits.
The operational impact of CVE-2017-8593 is severe and far-reaching given the widespread deployment of affected Windows versions across enterprise environments and consumer systems. Organizations running vulnerable systems face significant risk of unauthorized access, data breaches, and complete system compromise. The vulnerability can be exploited through various attack vectors including malicious email attachments, compromised websites, or social engineering campaigns that trick users into executing malicious code. Once successfully exploited, attackers can establish persistent backdoors, steal sensitive information, deploy additional malware, or use the compromised system as a launch point for further attacks within the network. The widespread availability of exploit code and the relatively simple nature of the attack make this vulnerability particularly attractive to threat actors, leading to its rapid adoption in various cyber campaigns and advanced persistent threat operations.
Mitigation strategies for CVE-2017-8593 require immediate implementation of Microsoft security patches and updates released as part of the July 2017 security bulletin. Organizations should prioritize patching all affected systems and implement additional security controls such as application whitelisting, restricted user privileges, and enhanced monitoring of system calls related to graphics operations. Network segmentation and intrusion detection systems should be configured to monitor for suspicious activities that might indicate exploitation attempts. Security teams should also conduct thorough vulnerability assessments to identify systems running vulnerable versions of Windows and ensure proper patch management procedures are in place. The vulnerability demonstrates the importance of maintaining up-to-date security patches and highlights the critical need for organizations to implement comprehensive security hygiene practices that include regular vulnerability scanning, timely patch deployment, and continuous monitoring of system integrity to prevent exploitation of kernel-level vulnerabilities.