CVE-2015-6040 in Office
Summary
by MITRE
Microsoft Excel 2007 SP3, Excel 2010 SP2, Excel for Mac 2011, Excel 2016 for Mac, Office Compatibility Pack SP3, and Excel Viewer allow remote attackers to execute arbitrary code via a crafted Office document, aka "Microsoft Office Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 06/29/2022
The vulnerability identified as CVE-2015-6040 represents a critical memory corruption flaw affecting multiple versions of Microsoft Excel software across different platforms and operating systems. This vulnerability specifically impacts Excel 2007 SP3, Excel 2010 SP2, Excel for Mac 2011, Excel 2016 for Mac, Office Compatibility Pack SP3, and Excel Viewer applications. The flaw enables remote attackers to execute arbitrary code through the manipulation of crafted Office documents, making it a significant threat to enterprise and individual users who rely on Microsoft Office productivity suites for daily operations.
The technical nature of this vulnerability stems from improper memory handling within Excel's document parsing mechanisms when processing specially crafted Office files. When users open or interact with these malicious documents, the application's memory management routines fail to properly validate input data, leading to memory corruption that can be exploited to gain unauthorized code execution privileges. This type of vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions that can result in memory corruption and arbitrary code execution. The flaw operates at the application layer where Office documents are processed, making it particularly dangerous as it can be triggered simply by opening a malicious file without requiring additional user interaction beyond the initial document opening.
The operational impact of CVE-2015-6040 extends far beyond individual user compromise, potentially enabling attackers to establish persistent access to corporate networks through initial foothold acquisition. Attackers can leverage this vulnerability to deploy malware, establish backdoors, or conduct more sophisticated attacks such as privilege escalation and lateral movement within target environments. The widespread adoption of Microsoft Excel across organizations makes this vulnerability particularly attractive to threat actors, as successful exploitation can affect numerous systems simultaneously. The vulnerability's remote exploitation capability means that attackers do not need physical access to target systems, allowing them to compromise networks through phishing emails, malicious websites, or other remote attack vectors. This characteristic aligns with ATT&CK technique T1203, which describes exploitation of remote services, and T1059, which covers command and scripting interpreter usage.
Mitigation strategies for CVE-2015-6040 should encompass both immediate patching and defensive measures. Microsoft released security updates addressing this vulnerability through their regular security bulletins, and organizations must ensure all affected Excel installations receive the appropriate patches. System administrators should implement comprehensive patch management processes to maintain up-to-date Office installations across all endpoints. Additional defensive measures include implementing strict document handling policies, enabling macro security settings, deploying email filtering solutions, and conducting regular security awareness training for users. Network segmentation and monitoring solutions can help detect suspicious file access patterns, while endpoint protection platforms should be configured to scan Office documents for potential malicious content. Organizations should also consider implementing application whitelisting policies to restrict execution of unauthorized software, particularly in high-risk environments where the vulnerability could be exploited to compromise critical systems.