CVE-2005-1829 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 SP2 allows remote attackers to cause a denial of service (infinite loop and application crash) via two embedded files that call each other.
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Analysis
by VulDB Data Team • 05/07/2019
Microsoft Internet Explorer 6 Service Pack 2 contains a critical vulnerability that enables remote attackers to trigger a denial of service condition through specifically crafted embedded files. This vulnerability manifests when two malicious files are embedded within a web page and reference each other in a recursive manner, creating an infinite loop that consumes system resources and ultimately causes the browser application to crash. The flaw exists in the browser's handling of nested file references and demonstrates a classic example of improper input validation and resource management. This issue falls under the category of CWE-838, which describes insufficient input validation leading to resource exhaustion. The vulnerability represents a significant security concern as it can be exploited through web-based attacks without requiring any special privileges or user interaction beyond visiting a malicious webpage. Attackers can construct malicious web content that, when loaded in Internet Explorer 6 SP2, will initiate the recursive file loading process that leads to system resource depletion and application instability. The impact extends beyond simple denial of service as the infinite loop can cause the browser to become unresponsive, potentially affecting other system processes and consuming significant memory and cpu resources. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion. The flaw affects users who are running Internet Explorer 6 SP2 in their browser environment, particularly those who may encounter malicious web content or be targeted through drive-by download attacks. The vulnerability is particularly dangerous in enterprise environments where users may not be regularly updating their browser software, leaving them exposed to this type of resource exhaustion attack. Organizations should consider implementing web content filtering solutions and browser security policies to mitigate the risk. The technical nature of this vulnerability also highlights the importance of proper resource management in browser applications and demonstrates how seemingly benign file referencing mechanisms can be exploited for malicious purposes. This issue serves as a reminder of the critical need for robust input validation and proper handling of recursive references in web browser implementations.
The exploitation of this vulnerability requires minimal user interaction and can be effectively automated through malicious web content. Security researchers have noted that the infinite loop occurs during the parsing phase of the browser's rendering engine, where it attempts to resolve the circular references between the embedded files. The resource consumption pattern typically shows rapid memory allocation followed by application instability and eventual crash. This behavior is consistent with CWE-400, which addresses unchecked resource consumption, and demonstrates how improper handling of file references can lead to complete application failure. The vulnerability's impact is particularly severe given that Internet Explorer 6 SP2 was widely deployed in enterprise environments, making it a prime target for attackers seeking to disrupt business operations. Organizations with legacy systems running this version of Internet Explorer face significant risk from this vulnerability, as the browser lacks modern security features and regular updates. The attack vector is particularly concerning because it can be delivered through standard web browsing activities, making it difficult for users to avoid exposure. Network security teams should implement monitoring for unusual resource consumption patterns that might indicate exploitation attempts. The vulnerability also underscores the importance of maintaining up-to-date browser software and implementing security controls that prevent execution of potentially malicious content. This flaw represents a typical example of how browser security vulnerabilities can be exploited for denial of service attacks, highlighting the need for comprehensive browser security strategies that include regular updates, security patches, and proper application hardening measures. The technical implementation of this vulnerability demonstrates the critical importance of robust error handling and resource management in browser applications, as even simple circular references can lead to complete system instability. Organizations should prioritize immediate remediation through browser updates or alternative browser implementations to prevent exploitation of this vulnerability.