CVE-2016-3234 in Office
Summary
by MITRE
Microsoft Word 2007 SP3, Office 2010 SP2, Word 2010 SP2, Office Compatibility Pack SP3, Word Viewer, Word Automation Services on SharePoint Server 2010 SP2, Word Automation Services on SharePoint Server 2013 SP1, Office Web Apps 2010 SP2, and Office Web Apps Server 2013 SP1 allow remote attackers to obtain sensitive information from process memory via a crafted Office document, aka "Microsoft Office Information Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 08/23/2022
This vulnerability represents a critical information disclosure flaw in Microsoft Office applications that affects multiple versions including Word 2007 SP3, Office 2010 SP2, and various SharePoint and Web Apps versions. The vulnerability stems from improper handling of crafted Office documents that trigger memory access patterns exposing sensitive data from process memory. Attackers can exploit this weakness by crafting malicious documents that, when opened by vulnerable applications, cause the system to leak information through memory corruption or improper memory management during document parsing operations. The flaw falls under the category of information disclosure vulnerabilities as defined by CWE-200, which specifically addresses the exposure of sensitive information to unauthorized actors. This vulnerability is particularly concerning because it can be exploited remotely through email attachments or web-based document delivery mechanisms, making it a significant threat vector for enterprise environments where Office documents are frequently exchanged.
The technical implementation of this vulnerability involves specific memory access patterns that occur during document processing when Microsoft Office applications encounter malformed or specially crafted Office document structures. When these applications process maliciously constructed documents, they fail to properly validate input data, leading to memory access violations that inadvertently expose portions of process memory containing sensitive information such as encryption keys, user credentials, or other confidential data. The exploitation mechanism typically involves creating Office documents with malformed structures that trigger buffer overflows or memory corruption during parsing operations, causing the application to leak memory contents through various error handling mechanisms or memory management functions. This type of vulnerability is classified under ATT&CK technique T1059.005 for command and scripting interpreter, and T1068 for exploit for privilege escalation, as the information disclosure can lead to further exploitation opportunities within the compromised system.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked memory contents can contain highly sensitive data that can be leveraged for more sophisticated attacks. Organizations using affected Office versions face significant risks including potential credential theft, exposure of internal system information, and compromise of encryption keys used for document protection or communication security. The vulnerability affects not only desktop Office applications but also server-side automation services including Word Automation Services on SharePoint servers, making it a particularly dangerous flaw for enterprise document processing environments. Attackers can potentially use the leaked information to conduct targeted attacks against specific users or systems, perform advanced persistent threat operations, or exploit additional vulnerabilities discovered through the leaked data. The impact is further amplified in environments where Office documents are frequently processed through automated workflows or web applications, as the vulnerability can be exploited through multiple attack vectors including web-based document viewers and SharePoint document libraries.
Mitigation strategies for this vulnerability require immediate patching of all affected Microsoft Office versions with the corresponding security updates released by Microsoft. Organizations should implement strict document validation policies that scan and filter incoming Office documents before processing, particularly in high-risk environments or when dealing with external sources. Network segmentation and access controls should be implemented to limit the potential impact of successful exploitation, while monitoring systems should be deployed to detect unusual memory access patterns or information disclosure attempts. Security teams should also consider implementing application whitelisting policies that restrict execution of Office applications to known good binaries and ensure that all Office installations are kept current with security patches. The vulnerability demonstrates the importance of proper input validation and memory management practices in software development, as highlighted by CWE-125 for out-of-bounds read and CWE-772 for missing release of resource after effective lifetime. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other Office applications and third-party software components that may be subject to similar memory corruption issues.