CVE-2013-3891 in Word
Summary
by MITRE
Microsoft Word 2003 SP3 allows remote attackers to execute arbitrary code via a crafted Office document, aka "Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 05/26/2021
The vulnerability identified as CVE-2013-3891 represents a critical memory corruption flaw in Microsoft Word 2003 Service Pack 3 that enables remote code execution through maliciously crafted Office documents. This vulnerability falls under the broader category of memory safety issues that have historically plagued Microsoft Office applications, with the specific flaw manifesting as an improper handling of memory structures during document processing operations. The vulnerability is particularly concerning because it can be exploited remotely through various attack vectors including email attachments, web downloads, or malicious documents shared through collaboration platforms, making it a prime target for widespread exploitation campaigns.
The technical nature of this vulnerability stems from insufficient input validation and memory management within Word 2003's document parsing engine. When processing specially crafted Office documents containing malformed or oversized data structures, the application fails to properly validate memory boundaries, leading to buffer overflows or heap corruption conditions. This memory corruption can be leveraged by attackers to overwrite critical memory locations, potentially allowing them to inject and execute arbitrary code with the privileges of the victim user. The vulnerability is classified as a memory corruption issue that aligns with CWE-121, which specifically addresses stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios. These classifications underscore the fundamental nature of the flaw as a memory safety issue that can be exploited through improper memory handling during document processing operations.
The operational impact of CVE-2013-3891 extends beyond simple remote code execution, as it represents a significant threat vector for advanced persistent threats and targeted attacks. Attackers can craft malicious documents that appear legitimate to end users, exploiting the trust users place in Office documents while simultaneously bypassing many traditional security controls. The vulnerability's exploitation capability means that successful attacks can result in complete system compromise, data exfiltration, and establishment of persistent backdoors. Organizations running Word 2003 SP3 are particularly vulnerable since this version lacks modern exploit mitigation features such as address space layout randomization and data execution prevention that are standard in newer Office versions. The attack surface is further expanded by the fact that many enterprise environments still maintain legacy Word 2003 installations, creating a persistent threat vector that attackers can leverage to gain unauthorized access to sensitive corporate information.
Mitigation strategies for CVE-2013-3891 should prioritize immediate patching of affected systems, as Microsoft released security updates addressing this vulnerability through their regular security bulletin process. Organizations should implement comprehensive document sanitization policies that restrict the execution of macros and prevent automatic loading of potentially malicious content. Network-based protections including email filtering systems and web proxies should be configured to scan and block suspicious Office documents before they reach end users. Additionally, user education programs should emphasize the importance of verifying document sources and avoiding opening attachments from unknown senders. The vulnerability's characteristics align with tactics described in the MITRE ATT&CK framework under the initial access phase, specifically targeting the 'Phishing' and 'Exploitation of Vulnerabilities' techniques. Organizations should also consider implementing application whitelisting policies that restrict execution of Office applications to trusted environments and establish robust incident response procedures to detect and respond to potential exploitation attempts. Given the age of Word 2003 and its limited security features, the most effective long-term mitigation involves migrating to supported Office versions that include modern security enhancements and regular security updates.