CVE-2013-7332 in Internet Explorer
Summary
by MITRE
The Microsoft.XMLDOM ActiveX control in Microsoft Windows 8.1 and earlier does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, a similar issue to CVE-2003-1564.
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Analysis
by VulDB Data Team • 04/12/2025
The vulnerability described in CVE-2013-7332 represents a critical recursion detection flaw within Microsoft's XML Document Object Model ActiveX control that affects Windows 8.1 and earlier operating systems. This weakness specifically manifests in the control's inability to properly identify and terminate recursive entity expansion processes, creating a pathway for malicious actors to exploit the system through carefully crafted XML documents. The issue demonstrates a fundamental failure in input validation and resource management within the XML parsing mechanism, where the control fails to implement adequate safeguards against excessive nesting levels that could lead to resource exhaustion.
The technical implementation of this vulnerability stems from the XML parser's handling of entity references within XML documents, where it processes nested entities without sufficient depth monitoring or recursion limits. When an attacker submits a malformed XML document containing numerous nested entity references, the parser continues to expand these entities recursively until system resources are completely consumed, resulting in denial of service conditions. This flaw operates at the core parsing layer of the XMLDOM control and affects any application or service that relies on this component for XML processing, making it particularly dangerous in web applications and server environments where XML data processing is common.
The operational impact of this vulnerability extends beyond simple service disruption to encompass significant resource consumption patterns that can overwhelm system capabilities. Attackers can craft XML documents that cause the XMLDOM control to consume excessive memory and CPU cycles, potentially leading to system instability, application crashes, or complete system unresponsiveness. The vulnerability's similarity to CVE-2003-1564 indicates a persistent architectural weakness in how Microsoft handles XML entity expansion, suggesting that this issue has existed for years and affects multiple versions of the Windows operating system. This type of vulnerability directly maps to CWE-400, which classifies "Uncontrolled Resource Consumption" as a critical weakness in software design, particularly when dealing with recursive parsing operations.
Organizations affected by this vulnerability face significant operational risks including potential service outages, resource exhaustion attacks, and system instability that could impact business continuity. The attack vector requires minimal technical expertise to exploit, making it particularly dangerous in environments where XML processing is common. From a cybersecurity perspective, this vulnerability represents a classic example of how seemingly benign parsing operations can become attack surfaces when proper recursion limits are not implemented. The issue aligns with ATT&CK technique T1499.004, which covers "Resource Hijacking" through excessive resource consumption, and demonstrates how attackers can leverage XML parsing weaknesses to perform denial of service attacks. Mitigation strategies should focus on implementing strict entity expansion limits, monitoring XML processing activities, and ensuring timely patch deployment for affected Windows versions. The vulnerability underscores the importance of proper input validation and resource management in security-critical components, particularly those handling untrusted data inputs.