CVE-2015-2520 in Excel
Summary
by MITRE
Microsoft Excel 2007 SP3, Excel 2010 SP2, Excel for Mac 2011 and 2016, 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 • 06/24/2024
The vulnerability identified as CVE-2015-2520 represents a critical memory corruption flaw within Microsoft Excel applications across multiple versions and platforms. This vulnerability specifically affects Excel 2007 SP3, Excel 2010 SP2, Excel for Mac 2011 and 2016, Office Compatibility Pack SP3, and Excel Viewer, making it a widespread issue that impacts a significant portion of the Microsoft Office ecosystem. The flaw stems from improper handling of memory operations when processing specially crafted Office documents, creating opportunities for remote code execution attacks that can compromise entire systems.
The technical nature of this vulnerability falls under CWE-125, which describes out-of-bounds read conditions where an application accesses memory beyond its allocated boundaries. Attackers can exploit this weakness by crafting malicious Office documents that, when opened by vulnerable Excel versions, trigger memory corruption during document parsing operations. The vulnerability typically manifests through improper validation of input data structures within Excel's document processing engine, allowing attackers to manipulate memory pointers and execute arbitrary code with the privileges of the compromised user. This memory corruption occurs during the parsing of specific file formats, particularly those involving complex data structures or embedded objects within Office documents.
The operational impact of CVE-2015-2520 extends far beyond simple data corruption, as successful exploitation can result in complete system compromise. Remote attackers can leverage this vulnerability to install malware, steal sensitive information, establish persistence mechanisms, or escalate privileges within the compromised environment. The attack surface is particularly concerning given that Excel documents are commonly shared via email attachments, file transfers, and web downloads, making this vulnerability highly exploitable in real-world scenarios. Organizations that rely heavily on Office document processing are particularly at risk, as the vulnerability can be triggered simply by opening a malicious file, requiring no additional user interaction beyond the standard document opening process.
Mitigation strategies for this vulnerability should include immediate deployment of Microsoft security updates and patches released in response to this CVE. System administrators should implement comprehensive email filtering and document validation policies to prevent malicious Office documents from reaching end users. Network segmentation and endpoint protection solutions can provide additional layers of defense by monitoring for suspicious file access patterns and blocking known malicious document signatures. The ATT&CK framework categorizes this vulnerability under the T1203 technique for "Exploitation for Client Execution" and T1059 for "Command and Scripting Interpreter," highlighting the need for both preventive measures and detection capabilities. Organizations should also consider implementing principle of least privilege access controls and regular security awareness training to reduce the risk of successful exploitation through social engineering vectors that might accompany these malicious documents.