CVE-2017-8744 in Excel
Summary
by MITRE
A remote code execution vulnerability exists in Excel Services, Microsoft Excel 2007 Service Pack 3, Microsoft Excel 2010 Service Pack 2, Microsoft Excel 2013 Service Pack 1, Microsoft Excel 2013 RT Service Pack 1, and Microsoft Excel 2016 when they fail to properly handle objects in memory, aka "Microsoft Office Memory Corruption Vulnerability". This CVE ID is unique from CVE-2017-8630, CVE-2017-8632, and CVE-2017-8731.
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Analysis
by VulDB Data Team • 01/12/2021
The vulnerability identified as CVE-2017-8744 represents a critical memory corruption flaw within Microsoft Office Excel Services and various Excel client versions including 2007 through 2016. This issue stems from the improper handling of objects in memory during Excel file processing operations, creating a remote code execution vector that can be exploited by malicious actors. The vulnerability specifically affects systems running Microsoft Excel 2007 Service Pack 3, Microsoft Excel 2010 Service Pack 2, Microsoft Excel 2013 Service Pack 1, Microsoft Excel 2013 RT Service Pack 1, and Microsoft Excel 2016, making it a widespread concern across multiple product lines.
The technical exploitation of this vulnerability occurs when Excel Services or Excel client applications process specially crafted malicious files that contain malformed objects in memory. When these objects are parsed and handled incorrectly, they can cause memory corruption that allows attackers to execute arbitrary code on the target system. This type of vulnerability falls under CWE-125: "Out-of-bounds Read" and CWE-787: "Out-of-bounds Write" classifications, representing memory safety issues that can lead to privilege escalation and complete system compromise. The flaw operates at the memory management level where the application fails to properly validate or sanitize object references during processing, creating opportunities for attackers to manipulate memory contents.
The operational impact of CVE-2017-8744 extends beyond simple remote code execution, as it can enable attackers to gain unauthorized access to sensitive systems and data. Organizations using affected Excel versions face significant risk when processing untrusted Excel files, particularly in environments where users have the ability to open files from external sources or web applications. The vulnerability can be exploited through various attack vectors including malicious email attachments, compromised websites, or files shared through collaborative platforms. According to ATT&CK framework, this vulnerability maps to T1059.005: "Command and Scripting Interpreter: Visual Basic" and T1203: "Exploitation for Client Execution," highlighting the potential for attackers to leverage this flaw for persistent access and lateral movement within networks.
Mitigation strategies for CVE-2017-8744 should focus on immediate patching of affected systems with Microsoft security updates, particularly the July 2017 security updates that addressed this specific vulnerability. Organizations should implement strict file validation policies, including disabling automatic execution of macros and implementing sandboxing techniques for Excel file processing. Network segmentation and monitoring can help detect suspicious file access patterns, while user education programs should emphasize the dangers of opening untrusted Excel files. Additional protective measures include configuring Microsoft Office to disable automatic loading of external content and implementing application whitelisting to prevent execution of unauthorized binaries. The vulnerability also underscores the importance of maintaining up-to-date security practices and adhering to Microsoft's recommended security configurations for Office applications, as this flaw demonstrates the critical nature of timely patch management in preventing exploitation of memory corruption vulnerabilities.