CVE-2011-3401 in Windows
Summary
by MITRE
ENCDEC.DLL in Windows Media Player and Media Center in Microsoft Windows XP SP2 and SP3, Windows Vista SP2, and Windows 7 Gold and SP1 allows remote attackers to execute arbitrary code via a crafted .dvr-ms file, aka "Windows Media Player DVR-MS Memory Corruption Vulnerability."
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Analysis
by VulDB Data Team • 01/06/2025
The vulnerability identified as CVE-2011-3401 represents a critical memory corruption flaw within the ENCDEC.DLL component of Windows Media Player and Media Center across multiple Windows operating systems including Windows XP SP2 and SP3, Windows Vista SP2, and Windows 7 Gold and SP1. This vulnerability operates through the processing of maliciously crafted .dvr-ms files which are Microsoft's Digital Video Recording format used for storing television recordings and other video content. The flaw manifests when the affected software attempts to parse these specially constructed files, leading to improper memory handling that can be exploited by remote attackers to execute arbitrary code on vulnerable systems.
The technical nature of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions where a program accesses memory beyond its allocated boundaries. The flaw occurs during the decoding process of .dvr-ms files where ENCDEC.DLL fails to properly validate input parameters and buffer boundaries, allowing attackers to craft malicious files that trigger memory corruption. When Windows Media Player or Media Center attempts to process these crafted files, the memory corruption can be leveraged to overwrite critical memory locations, potentially leading to privilege escalation or complete system compromise. This vulnerability is particularly concerning as it can be triggered remotely through various attack vectors including email attachments, web downloads, or malicious websites that automatically attempt to play the malicious media content.
The operational impact of this vulnerability extends beyond simple code execution, as it represents a significant attack surface for threat actors seeking to compromise Windows systems. The vulnerability affects widely deployed media player software that is often automatically invoked when users encounter media content, making exploitation relatively straightforward. Attackers can leverage this vulnerability through social engineering campaigns targeting end users, or through automated scanning tools that identify systems running vulnerable versions of Windows Media Player. The vulnerability's remote execution capability makes it particularly dangerous in enterprise environments where media files might be automatically processed by various applications, potentially allowing attackers to gain unauthorized access to sensitive systems. This flaw directly relates to ATT&CK technique T1203, which involves exploiting vulnerabilities in media players and multimedia applications to achieve initial access or privilege escalation.
Mitigation strategies for CVE-2011-3401 should include immediate deployment of Microsoft security patches and updates, particularly the cumulative security updates released in August 2011 that addressed this specific vulnerability. Organizations should implement network segmentation and content filtering to prevent automatic execution of potentially malicious media files, particularly .dvr-ms files that are commonly associated with this attack vector. System administrators should disable Windows Media Player and Media Center functionality where these applications are not required, or implement application whitelisting policies that restrict execution of media players to trusted environments only. Additionally, users should be educated about the risks of opening unexpected media files and should be trained to avoid downloading content from untrusted sources. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates how media processing components can serve as attack vectors in modern threat landscapes, making comprehensive vulnerability management essential for protecting enterprise environments against similar threats.