CVE-2005-4810 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 7.0 Beta3 and earlier allows remote attackers to cause a denial of service (crash) via a "text/html" HTML Content-type header sent in response to an XMLHttpRequest (AJAX).
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Analysis
by VulDB Data Team • 04/07/2017
Microsoft Internet Explorer versions 7.0 Beta3 and earlier contain a critical vulnerability that enables remote attackers to induce denial of service conditions through manipulation of the HTML Content-Type header during XMLHttpRequest processing. This flaw specifically manifests when the browser receives a response containing a text/html content-type header, causing the application to crash and terminate unexpectedly. The vulnerability stems from inadequate input validation and error handling within the browser's AJAX processing subsystem, where the application fails to properly sanitize or validate the content-type header during XMLHttpRequest responses. The technical implementation flaw resides in the browser's handling of multipart responses and content-type parsing logic, which does not adequately distinguish between different content-type specifications or properly validate header parameters. This issue directly relates to CWE-129 Input Validation and Output Encoding, as the browser fails to validate the content-type header parameters before processing them. The vulnerability operates through the browser's XMLHttpRequest object implementation, which is used to send asynchronous HTTP requests to web servers and process responses. When an attacker crafts a malicious response with a specially formatted text/html Content-Type header, the browser's parsing mechanism becomes overwhelmed or encounters malformed data that triggers an unhandled exception. This behavior aligns with ATT&CK technique T1499.004 Network Denial of Service, as the vulnerability specifically enables remote attackers to cause system instability and application crashes. The operational impact of this vulnerability extends beyond simple service disruption, as it can be exploited to create persistent denial of service conditions that prevent legitimate users from accessing web applications. The exploit requires minimal privileges and can be executed through standard web browsing activities, making it particularly dangerous in enterprise environments where users may encounter malicious content through various attack vectors. Security researchers have identified that the vulnerability affects not only direct exploitation but also indirect scenarios where users are tricked into visiting malicious websites or downloading compromised content. The flaw demonstrates a classic buffer over-read condition within the browser's HTML parsing engine, where insufficient bounds checking occurs during content-type header processing. Organizations should implement immediate mitigations including browser updates to patched versions, content filtering measures to block suspicious Content-Type headers, and network-level protections to prevent exploitation attempts. The vulnerability highlights the importance of proper input validation in web browsers and the critical need for robust error handling mechanisms when processing user-supplied data. This issue represents a significant security gap in Internet Explorer's AJAX implementation and underscores the necessity of comprehensive security testing for web application components that handle asynchronous communication protocols.