CVE-2017-8587 in Windows
Summary
by MITRE
Windows Explorer 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 allows a denial of service vulnerability when it attempts to open a non-existent file, aka "Windows Explorer Denial of Service Vulnerability".
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Analysis
by VulDB Data Team • 09/14/2024
The vulnerability identified as CVE-2017-8587 represents a critical denial of service flaw within Windows Explorer component across multiple Windows operating systems including Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, and Windows 10 Gold and 1511 versions. This vulnerability specifically manifests when Windows Explorer attempts to process or open a non-existent file path, creating a scenario where the system becomes unresponsive or crashes entirely. The flaw operates at the file system interaction layer where the explorer.exe process fails to properly handle malformed or invalid file references, leading to system instability and potential service disruption.
From a technical perspective, the vulnerability stems from inadequate input validation within the Windows Explorer file handling mechanism. When a user or application attempts to access a file that does not exist, the explorer component lacks proper error handling routines to gracefully manage this scenario. This weakness allows an attacker to construct malicious file paths or trigger specific file access patterns that cause the explorer.exe process to enter an infinite loop or crash state. The vulnerability aligns with CWE-20, which describes improper input validation, and specifically demonstrates how insufficient validation of file system access parameters can lead to system instability. The flaw operates at the application level within the Windows shell environment, making it particularly dangerous as it can affect user productivity and system availability.
The operational impact of this vulnerability extends beyond simple system crashes, as it can be exploited to create persistent denial of service conditions that affect user experience and system reliability. When Windows Explorer becomes unresponsive, users lose access to file browsing functionality and may experience complete desktop freezes, forcing system administrators to restart affected machines manually. This vulnerability particularly affects enterprise environments where multiple users access shared file systems, as a single malicious file reference can potentially disrupt operations across numerous workstations. The exploitability of this vulnerability is relatively straightforward, requiring only the ability to trigger Windows Explorer to attempt opening a non-existent file, making it a significant concern for organizations with limited security controls.
Mitigation strategies for CVE-2017-8587 should prioritize immediate patch deployment through Microsoft's security updates, specifically addressing the Windows Explorer denial of service vulnerability. System administrators should implement network segmentation to limit file access from untrusted sources and consider disabling unnecessary file sharing protocols that might expose vulnerable systems. The vulnerability demonstrates characteristics aligned with ATT&CK technique T1489, which involves denying system services through various methods including process termination and resource exhaustion. Organizations should also establish monitoring protocols to detect unusual explorer.exe behavior patterns and implement automated response mechanisms to isolate affected systems. Additionally, user education regarding safe file handling practices and the avoidance of suspicious file references can provide an additional layer of defense against exploitation attempts.