CVE-2006-3864 in Office
Summary
by MITRE
Unspecified vulnerability in mso.dll in Microsoft Office 2000, XP, and 2003, and Microsoft PowerPoint 2000, XP, and 2003, allows remote user-assisted attackers to execute arbitrary code via a malformed record in a (1) .DOC, (2) .PPT, or (3) .XLS file that triggers memory corruption, related to an "array boundary condition" (possibly an array index overflow), a different vulnerability than CVE-2006-3434, CVE-2006-3650, and CVE-2006-3868.
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Analysis
by VulDB Data Team • 04/24/2026
This vulnerability resides in the mso.dll component of Microsoft Office and PowerPoint versions spanning from 2000 through 2003, representing a critical memory corruption flaw that enables remote code execution through maliciously crafted Office documents. The vulnerability specifically manifests when processing malformed records within .DOC, .PPT, or .XLS file formats, exploiting what is classified as an array boundary condition or array index overflow. This particular weakness falls under the broader category of memory safety issues that have historically plagued Microsoft Office applications, making them prime targets for exploitation by threat actors seeking to leverage remote code execution capabilities. The vulnerability's classification as a user-assisted attack means that victims must willingly open the malicious file, typically through social engineering or phishing campaigns, though the attack vector remains highly dangerous due to the elevated privileges that Office applications typically operate with.
The technical implementation of this vulnerability stems from improper bounds checking within the mso.dll library when parsing structured data within Office document formats. When Office applications encounter malformed records containing oversized or improperly indexed arrays, the application's memory management system fails to validate these inputs correctly, leading to memory corruption that can be leveraged to execute arbitrary code. This flaw represents a classic buffer overflow scenario where the application attempts to write data beyond the allocated memory boundaries, potentially overwriting critical program structures or executing malicious code injected into the memory space. The array index overflow condition specifically indicates that the application uses an index value that exceeds the valid range of the array, causing unpredictable behavior and potential code execution. This type of vulnerability aligns with CWE-129, which describes improper validation of array indices, and also relates to CWE-787, which covers out-of-bounds write conditions in array data structures.
The operational impact of this vulnerability extends beyond simple remote code execution, as it provides attackers with a mechanism to compromise entire systems through targeted Office document delivery. Attackers can craft malicious documents that, when opened by unsuspecting users, trigger the memory corruption and execute malicious payloads with the privileges of the user running Office. This creates significant risk for enterprise environments where Office documents are frequently shared and opened by multiple users. The vulnerability's presence in multiple Office versions from 2000 through 2003 means that organizations with legacy systems remain particularly vulnerable, as these older versions often lack modern security mitigations such as DEP, ASLR, and stack canaries. The attack surface is further expanded due to the widespread use of these Office versions in corporate environments, making the exploitation of this vulnerability particularly attractive to threat actors targeting organizations with outdated software deployments.
Mitigation strategies for this vulnerability require a multi-layered approach combining immediate patching, user education, and administrative controls. Microsoft released security updates addressing this vulnerability as part of their regular patching cycle, and organizations should prioritize applying these patches immediately to all affected systems. Network-based mitigations such as email filtering and sandboxing of Office documents can provide additional protection layers, particularly in environments where immediate patching is not feasible. Security controls should include disabling automatic execution of macros in Office applications, implementing strict file validation policies, and maintaining current antivirus signatures that can detect known malicious Office document patterns. From an ATT&CK perspective, this vulnerability maps to techniques involving execution through Office applications, specifically T1204.002 which covers "User Execution: Malicious File," and T1059.005 which covers "Command and Scripting Interpreter: Visual Basic." Organizations should implement monitoring for suspicious Office document opening patterns and establish incident response procedures specifically addressing potential exploitation of this type of memory corruption vulnerability. The vulnerability also highlights the importance of maintaining up-to-date software inventory and implementing proper software lifecycle management to prevent deployment of vulnerable legacy applications in production environments.