CVE-2016-3284 in Office
Summary
by MITRE
Microsoft Excel 2007 SP3, Excel 2010 SP2, Excel 2013 SP1, Excel 2013 RT SP1, Excel 2016, 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."
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 09/01/2022
The Microsoft Office Memory Corruption Vulnerability identified as CVE-2016-3284 represents a critical security flaw affecting multiple versions of Microsoft Excel software across different platforms and operating systems. This vulnerability resides within the parsing mechanisms of Excel's handling of Office document formats, specifically targeting memory management functions that process structured data within spreadsheet files. The flaw manifests when Excel encounters specially crafted Office documents that contain malformed data structures designed to trigger unexpected behavior in the application's memory allocation and deallocation processes.
The technical nature of this vulnerability falls under the category of memory corruption, which is classified as CWE-121 in the Common Weakness Enumeration catalog. This weakness occurs when a program attempts to write data beyond the boundaries of allocated memory buffers, potentially leading to arbitrary code execution. The vulnerability exploits the way Excel processes certain file format elements, particularly those related to cell formatting, data validation, and structured references within spreadsheets. Attackers can construct malicious Office documents that, when opened by vulnerable Excel versions, cause memory corruption through improper handling of data structures such as cell ranges, formula expressions, or formatting properties.
From an operational perspective, this vulnerability presents a significant risk to enterprise environments where users frequently open documents from untrusted sources or receive email attachments containing potentially malicious content. The remote execution aspect means that attackers can deliver malicious documents through various vectors including email, web downloads, or compromised file sharing services without requiring local access to the target system. When exploited, the vulnerability allows attackers to execute arbitrary code with the privileges of the logged-on user, potentially leading to complete system compromise, data exfiltration, or deployment of additional malware. The impact extends beyond individual users to entire organizations as Excel documents are commonly shared through collaborative platforms and email systems.
Organizations should implement multiple layers of defense to mitigate this vulnerability effectively. The primary mitigation involves applying the security updates released by Microsoft as part of their regular patching schedule, specifically targeting the versions mentioned in the CVE description including Excel 2007 SP3, Excel 2010 SP2, Excel 2013 SP1, Excel 2013 RT SP1, Excel 2016, Excel for Mac 2011, Excel 2016 for Mac, Office Compatibility Pack SP3, and Excel Viewer. Additionally, security controls should include implementing strict email filtering policies to prevent malicious Office documents from reaching users, disabling automatic execution of macros in Office applications, and employing application whitelisting solutions that restrict execution of unauthorized software. Network-based protections such as intrusion prevention systems and web application firewalls can also help detect and block attempts to deliver malicious Office documents through web-based attack vectors. The vulnerability's classification under the ATT&CK framework as part of the initial access and execution phases highlights the importance of comprehensive endpoint protection strategies that combine traditional antivirus solutions with behavioral monitoring and advanced threat detection capabilities.