CVE-2013-6801 in Word
Summary
by MITRE
Microsoft Word 2003 SP2 and SP3 on Windows XP SP3 allows remote attackers to cause a denial of service (CPU consumption) via a malformed .doc file containing an embedded image, as demonstrated by word2003forkbomb.doc, related to a "fork bomb" issue.
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Analysis
by VulDB Data Team • 12/23/2024
Microsoft Word 2003 SP2 and SP3 running on Windows XP SP3 systems are vulnerable to a denial of service attack through malformed .doc files containing embedded images that trigger excessive cpu consumption. This vulnerability represents a classic fork bomb scenario where a specially crafted document causes the word processing application to enter an infinite loop or resource exhaustion state. The attack vector specifically exploits how Word handles embedded image data within document files, creating a condition where the application continuously processes malformed image structures without proper bounds checking or resource limits.
The technical flaw resides in the document parsing mechanism of Microsoft Word 2003, where the application fails to properly validate or sanitize embedded image data during document loading. When a malicious .doc file containing crafted image metadata is opened, the parsing routine becomes trapped in a recursive or iterative processing loop that consumes cpu cycles indefinitely. This behavior aligns with CWE-400 vulnerability category related to Uncontrolled Resource Consumption, where the application does not properly limit resource usage during processing of untrusted input. The vulnerability demonstrates a lack of proper input validation and resource management controls that should prevent such pathological behavior in document processing applications.
The operational impact of this vulnerability extends beyond simple denial of service as it can render the affected system unusable for legitimate document processing tasks. Attackers can exploit this weakness by distributing malicious documents through various channels including email attachments, web downloads, or removable media. The sustained cpu consumption can lead to system performance degradation, application crashes, or complete system lockup depending on the severity of the resource exhaustion. This vulnerability particularly affects enterprise environments where Word 2003 is still in use, as the application remains vulnerable even after Windows XP SP3 has been patched, since the issue lies within the application layer rather than the operating system.
Organizations should implement immediate mitigations including disabling automatic document opening for unknown sources, implementing strict email filtering policies, and deploying network-based intrusion detection systems to identify suspicious document traffic. The recommended approach involves updating to supported versions of Microsoft Office that have addressed this vulnerability through proper input validation and resource management controls. Additionally, system administrators should consider implementing application whitelisting policies that restrict execution of older Word versions and ensure that users are trained to recognize potentially malicious document attachments. This vulnerability also aligns with ATT&CK technique T1499 related to Network Denial of Service, where adversaries leverage application-specific weaknesses to consume system resources and disrupt normal operations. The attack demonstrates the importance of proper input validation and resource management in preventing exploitation of application-level vulnerabilities that can be leveraged for persistent disruption of service availability.