CVE-2017-8537 in Windows
Summary
by MITRE
The Microsoft Malware Protection Engine running on Microsoft Forefront and Microsoft Defender 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, Microsoft Exchange Server 2013 and 2016, does not properly scan a specially crafted file leading to denial of service. aka "Microsoft Malware Protection Engine Denial of Service Vulnerability", a different vulnerability than CVE-2017-8535, CVE-2017-8536, CVE-2017-8539, and CVE-2017-8542.
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Analysis
by VulDB Data Team • 12/23/2025
The Microsoft Malware Protection Engine vulnerability CVE-2017-8537 represents a critical denial of service flaw that affected multiple Microsoft products including Forefront, Microsoft Defender, and various Windows operating systems from 2008 through 2016. This vulnerability specifically targets the malware scanning functionality of the engine, creating a condition where specially crafted malicious files can cause the system to become unresponsive or crash entirely. The flaw manifests when the engine processes files that contain malformed or crafted data structures designed to exploit memory handling inconsistencies within the scanning process. This vulnerability is distinct from other related issues such as CVE-2017-8535 through CVE-2017-8542, each addressing different aspects of the malware protection engine's functionality.
The technical implementation of this vulnerability stems from improper input validation within the Microsoft Malware Protection Engine's file processing routines. When the engine encounters a specially crafted file that triggers memory corruption or buffer overflow conditions during analysis, it fails to properly handle the malformed input and instead crashes or becomes unresponsive. This behavior aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-129, which covers improper validation of array indices. The vulnerability operates at the kernel level within the Windows Defender service, making it particularly dangerous as it can affect system stability and availability across enterprise environments. Attackers can leverage this flaw by sending malicious files through email attachments, file downloads, or other vectors that would normally be scanned by the malware protection engine.
The operational impact of CVE-2017-8537 extends beyond simple system crashes to potentially disrupt critical business operations in enterprise environments. Organizations relying on Microsoft Defender or Forefront for endpoint protection face significant risk of service disruption when the malware engine becomes unresponsive, leading to potential gaps in security coverage. The vulnerability affects systems running 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 Microsoft Exchange Server 2013 and 2016. This broad scope means that enterprises with diverse operating system environments are all at risk, particularly those with legacy systems that may not receive timely updates. The vulnerability can be exploited through various attack vectors including phishing emails, compromised websites, or file-sharing systems where users might inadvertently trigger the malware scanning process on malicious files.
Mitigation strategies for CVE-2017-8537 require immediate action from system administrators and security teams across affected organizations. The primary solution involves installing the Microsoft security update released in August 2017, which patches the memory handling issues within the malware protection engine. Organizations should also implement additional protective measures including network segmentation to limit file transfer capabilities, enhanced email filtering to prevent malicious attachments from reaching users, and regular monitoring of system logs for signs of the vulnerability being exploited. From an ATT&CK framework perspective, this vulnerability maps to T1070.004 - Indicator Removal on Host, as it represents a mechanism that can be used to disrupt system availability, and T1059.001 - Command and Scripting Interpreter, as attackers may use the vulnerability to execute commands through crafted file delivery. Security teams should also consider implementing network-based detection measures to identify potential exploitation attempts and maintain detailed incident response procedures to address potential system disruptions caused by this vulnerability.