CVE-2006-3445 in Windows
Summary
by MITRE
Integer overflow in the ReadWideString function in agentdpv.dll in Microsoft Agent on Microsoft Windows 2000 SP4, XP SP2, and Server 2003 up to SP1 allows remote attackers to execute arbitrary code via a large length value in an .ACF file, which results in a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 04/27/2026
The vulnerability described in CVE-2006-3445 represents a critical integer overflow flaw within Microsoft Agent's agentdpv.dll component that affects multiple Windows operating systems including Windows 2000 SP4, Windows XP SP2, and Windows Server 2003 up to SP1. This vulnerability resides in the ReadWideString function which processes .ACF files, commonly used for defining agent characters and their behaviors. The flaw occurs when the function fails to properly validate input parameters, specifically the length field within these files, leading to a situation where an attacker can manipulate the size parameter to trigger unexpected behavior in memory allocation.
The technical implementation of this vulnerability stems from improper integer handling within the agentdpv.dll library where a 32-bit integer overflow occurs during string length calculations. When an attacker crafts a malicious .ACF file containing an oversized length value, the ReadWideString function processes this value without adequate bounds checking, resulting in a heap-based buffer overflow condition. This overflow allows attackers to overwrite adjacent memory locations, potentially corrupting program execution flow and enabling arbitrary code execution. The vulnerability specifically targets the heap memory management system where dynamic buffers are allocated, making it particularly dangerous as it can be exploited to gain control over the executing process.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a means to compromise systems running vulnerable versions of Microsoft Agent. The attack vector requires remote exploitation through the delivery of a malicious .ACF file, which can be embedded in web content, email attachments, or downloaded files. Once executed, the vulnerability allows attackers to escalate privileges, install malware, or establish persistent access to affected systems. The widespread deployment of Microsoft Agent across enterprise environments and the ease of delivery through common attack vectors make this vulnerability particularly attractive to threat actors. The vulnerability also demonstrates weaknesses in input validation and memory safety practices that were prevalent in software development during the early 2000s.
Mitigation strategies for CVE-2006-3445 should focus on immediate patching of affected systems through Microsoft security updates, as well as administrative controls to restrict execution of .ACF files from untrusted sources. Organizations should implement network-based protections such as content filtering and web application firewalls to prevent delivery of malicious .ACF files. Additionally, system hardening measures including disabling Microsoft Agent where not required, implementing least privilege principles, and monitoring for suspicious file execution patterns can significantly reduce the attack surface. From a cybersecurity perspective, this vulnerability aligns with CWE-190, Integer Overflow or Wraparound, and maps to attack techniques in the MITRE ATT&CK framework under T1059 for command and scripting interpreter and T1068 for exploit for privilege escalation. The vulnerability also demonstrates the importance of proper input validation and memory safety practices that became central to modern secure coding standards and defensive measures against similar classes of vulnerabilities.