CVE-2013-7331 in Windows
Summary
by MITRE
The Microsoft.XMLDOM ActiveX control in Microsoft Windows 8.1 and earlier allows remote attackers to determine the existence of local pathnames, UNC share pathnames, intranet hostnames, and intranet IP addresses by examining error codes, as demonstrated by a res:// URL, and exploited in the wild in February 2014.
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Analysis
by VulDB Data Team • 04/22/2026
The vulnerability identified as CVE-2013-7331 represents a significant information disclosure flaw within Microsoft's XMLDOM ActiveX control, which was prevalent in Windows 8.1 and earlier operating systems. This weakness specifically affects the control's handling of error responses when processing resource URLs, creating an avenue for attackers to enumerate sensitive system information through carefully crafted malicious requests. The vulnerability operates by leveraging the control's inconsistent error code reporting mechanisms, which inadvertently leak information about the underlying system's file structure and network configuration. The issue was particularly concerning because it allowed remote adversaries to perform reconnaissance activities without requiring any special privileges or authentication credentials, making it a prime target for initial access and enumeration phases of cyber attacks.
The technical exploitation of this vulnerability occurs through the manipulation of res:// URLs, which are designed to reference resources within the system. When the XMLDOM control processes these malformed or malicious URLs, it returns error codes that contain specific information about the existence or non-existence of particular file paths, UNC shares, or network resources. This information leakage happens because the control's error handling logic does not properly sanitize or abstract the error responses, allowing attackers to distinguish between different types of system resources based on the specific error codes returned. The vulnerability is classified under CWE-200, which deals with information exposure, and specifically demonstrates how improper error handling can lead to unintended information disclosure. The attack vector is particularly dangerous because it operates entirely through the ActiveX control interface, which is commonly enabled in Internet Explorer environments and can be triggered through web-based attacks.
The operational impact of CVE-2013-7331 extends far beyond simple information gathering, as it enables attackers to perform comprehensive reconnaissance of target systems and networks. By exploiting this vulnerability, threat actors could map internal network structures, identify active servers and services, and discover potentially sensitive resources within the organization's infrastructure. The ability to enumerate local pathnames provides attackers with insights into the system's file structure, while UNC share enumeration can reveal network resources and potentially sensitive file shares. Intranet hostname and IP address enumeration capabilities allow for the identification of internal network topology, which can be used to plan more sophisticated attacks such as internal network pivoting or targeted exploitation of specific systems. This vulnerability was actively exploited in the wild during February 2014, demonstrating its real-world threat potential and the importance of addressing such information disclosure issues before they can be leveraged for more serious attacks.
Organizations affected by this vulnerability should implement multiple layers of mitigation strategies to address the information disclosure risk. The most effective immediate solution involves disabling or removing the vulnerable ActiveX control from affected systems, particularly in Internet Explorer environments where it was most commonly exploited. System administrators should also implement proper network segmentation and access controls to limit the potential impact of information disclosure, ensuring that even if attackers can enumerate some system resources, they cannot easily access or exploit the discovered information. Security monitoring should be enhanced to detect unusual patterns of URL processing or error code generation that might indicate exploitation attempts. Additionally, organizations should consider implementing application whitelisting policies to prevent unauthorized ActiveX controls from executing, and ensure that all systems are properly patched and updated to prevent exploitation of this and similar vulnerabilities. The ATT&CK framework categorizes this vulnerability under T1082, which covers system information discovery, highlighting how such information disclosure can serve as a foundation for more comprehensive attack campaigns.