CVE-2017-8509 in Office
Summary
by MITRE
A remote code execution vulnerability exists in Microsoft Office when the software fails to properly handle objects in memory, aka "Office Remote Code Execution Vulnerability". This CVE ID is unique from CVE-2017-8510, CVE-2017-8511, CVE-2017-8512, CVE-2017-0260, and CVE-2017-8506.
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Analysis
by VulDB Data Team • 12/28/2020
The vulnerability described in CVE-2017-8509 represents a critical remote code execution flaw within Microsoft Office applications that stems from improper handling of objects in memory. This weakness specifically affects Microsoft Office products including Word, Excel, and PowerPoint, making it a significant threat vector for cyber attackers seeking to compromise enterprise environments. The vulnerability arises when Office applications process maliciously crafted documents that contain specially constructed objects designed to trigger memory corruption during normal document operations. This flaw allows attackers to execute arbitrary code on affected systems with the privileges of the logged-on user, potentially leading to complete system compromise and lateral movement within network infrastructures.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where applications fail to properly validate memory access boundaries. The flaw occurs during the processing of structured document formats such as .doc, .xls, and .ppt files, where Office applications attempt to parse and render embedded objects without adequate bounds checking. When malicious objects are embedded within these documents, they can cause the application to read beyond allocated memory regions, leading to unpredictable behavior including code execution. Attackers can exploit this by crafting specially formatted documents that trigger the memory corruption when opened by vulnerable Office versions, effectively bypassing typical security controls and operating system protections.
The operational impact of CVE-2017-8509 extends far beyond individual user compromise, as it provides attackers with a powerful tool for establishing persistent access within target networks. Once executed, the remote code execution capability allows threat actors to install backdoors, exfiltrate sensitive data, deploy additional malware payloads, and conduct reconnaissance activities without detection. This vulnerability is particularly dangerous in enterprise environments where Office applications are frequently used and documents are shared across multiple systems. The attack surface is significantly broadened as users may unknowingly open malicious documents from email attachments, shared network drives, or web downloads, making this vulnerability a prime target for phishing campaigns and targeted attacks. The vulnerability's similarity to other related CVEs such as CVE-2017-8510 and CVE-2017-8511 demonstrates a pattern of memory corruption issues within Microsoft Office products, indicating a systemic weakness in the document parsing and rendering components.
Mitigation strategies for CVE-2017-8509 should encompass both immediate patch management and defensive operational measures. Microsoft released security updates addressing this vulnerability through the August 2017 security bulletin, and organizations must prioritize applying these patches to all affected Office installations. In addition to patching, network administrators should implement email filtering solutions that block suspicious document attachments and utilize application whitelisting technologies to restrict execution of Office applications from untrusted sources. The implementation of exploit protection mechanisms such as Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) can provide additional defense-in-depth layers. Organizations should also consider deploying sandboxing solutions that isolate document processing in secure environments and establish robust monitoring protocols to detect anomalous Office application behavior. From an ATT&CK framework perspective, this vulnerability maps to techniques such as T1204.002 (User Execution: Malicious File) and T1059.005 (Command and Scripting Interpreter: Visual Basic), highlighting the need for comprehensive endpoint protection and user awareness training to prevent exploitation attempts.