CVE-2016-7233 in Office
Summary
by MITRE
Microsoft Word 2007, Office 2010 SP2, Word 2010 SP2, Word for Mac 2011, Excel for Mac 2011, Word Viewer, Office Compatibility Pack SP3, Word Automation Services on SharePoint Server 2013 SP1, and Office Web Apps 2010 SP2 allow remote attackers to obtain sensitive information from process memory or cause a denial of service (out-of-bounds read) via a crafted Office document, aka "Microsoft Office Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 09/30/2022
This vulnerability affects multiple Microsoft Office products including Word 2007, Office 2010 SP2, Word 2010 SP2, Word for Mac 2011, Excel for Mac 2011, Word Viewer, Office Compatibility Pack SP3, Word Automation Services on SharePoint Server 2013 SP1, and Office Web Apps 2010 SP2. The flaw manifests as an out-of-bounds read condition that occurs when processing specially crafted Office documents. This vulnerability falls under CWE-125, which describes out-of-bounds read conditions where programs access memory locations beyond the intended buffer boundaries. The security implications are significant as attackers can leverage this weakness to extract sensitive information from process memory or trigger denial of service conditions. The vulnerability exists in the document parsing logic where Office applications fail to properly validate input data structures, particularly when handling malformed or crafted Office files. This allows remote attackers to manipulate memory access patterns and potentially read data that should remain confidential, creating information disclosure risks.
The technical exploitation of this vulnerability involves crafting malicious Office documents that contain malformed data structures designed to trigger the out-of-bounds read condition during document processing. When an affected Office application opens such a document, the parsing engine encounters unexpected data that causes it to access memory locations beyond allocated buffers. This can result in information disclosure where sensitive data from adjacent memory regions is exposed to the attacker, or in denial of service scenarios where the application crashes or becomes unresponsive. The vulnerability affects both desktop and web-based Office implementations, making it particularly dangerous as it can be exploited through various attack vectors including email attachments, web-based document viewers, and SharePoint document libraries. The attack surface is broad due to the widespread adoption of Microsoft Office across enterprise environments and the numerous deployment scenarios where these vulnerable applications might be encountered.
The operational impact of CVE-2016-7233 extends beyond simple information disclosure to encompass potential system compromise and business disruption. Organizations using affected Office versions face risks of data leakage from process memory, which could contain encryption keys, user credentials, or other sensitive operational data. The denial of service aspect creates availability issues that can disrupt productivity, particularly in environments where Office automation services are heavily utilized. This vulnerability aligns with ATT&CK technique T1059.005, which covers the use of Office applications for execution, as attackers might leverage this weakness to establish persistence or escalate privileges. The widespread nature of affected products means that enterprise networks are particularly vulnerable, as a single compromised document could affect multiple users across different platforms. Security teams must consider the potential for lateral movement through information disclosure, as the leaked memory contents could provide attackers with additional attack surface information.
Mitigation strategies for this vulnerability should focus on immediate patching of affected Office versions, as Microsoft released security updates addressing this specific issue. Organizations should implement strict document validation policies and consider sandboxing Office applications when processing untrusted documents. Network-based controls such as email filtering and web application firewalls can help prevent exploitation attempts by blocking malicious Office documents from reaching end users. The principle of least privilege should be enforced when running Office automation services, limiting the potential impact if exploitation occurs. Regular security awareness training for users can help reduce the risk of social engineering attacks that might deliver malicious documents. Additionally, implementing monitoring solutions that detect unusual Office application behavior or memory access patterns can aid in early detection of exploitation attempts. Organizations should also consider deploying endpoint protection solutions that can detect and prevent the execution of malicious Office documents, particularly those that might trigger memory access violations. The vulnerability serves as a reminder of the importance of maintaining current security patches and implementing defense-in-depth strategies to protect against sophisticated exploitation techniques.