CVE-2003-1105 in Internet Explorer
Summary
by MITRE
Unknown vulnerability in Internet Explorer 5.01 SP3 through 6.0 SP1 allows remote attackers to cause a denial of service (browser or Outlook Express crash) via HTML with certain input tags that are not properly rendered.
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Analysis
by VulDB Data Team • 01/02/2025
This vulnerability exists within the Microsoft Internet Explorer browser versions 5.01 Service Pack 3 through 6.0 Service Pack 1, representing a classic denial of service flaw that affects both the browser itself and Microsoft Outlook Express email client. The issue stems from improper handling of specific HTML input tags that trigger malformed rendering behavior in the affected software components. The vulnerability falls under the category of input validation and rendering flaws that have been classified under CWE-121 as buffer overflow conditions and CWE-122 as buffer overflow vulnerabilities. Attackers can exploit this weakness by crafting malicious HTML content containing specially formatted input tags that cause the browser to crash or freeze during rendering operations.
The technical implementation of this vulnerability involves the browser's HTML parser encountering malformed input elements that are not properly sanitized or validated before processing. When Internet Explorer attempts to render these malformed tags, the parsing engine fails to handle the malformed data correctly, leading to memory corruption or stack overflow conditions that ultimately result in application termination. The flaw is particularly concerning because it can be triggered through email content when Outlook Express processes HTML messages, or through web-based attacks when users visit malicious websites. This cross-platform impact means that both desktop browser usage and email client operations are vulnerable to the same exploitation vectors.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more sophisticated attack vectors. While the primary effect is a denial of service condition causing browser or email client crashes, this weakness can serve as a foundation for more complex exploitation techniques. Security researchers have noted that such rendering flaws often provide footholds for subsequent attacks, as they can be combined with other vulnerabilities to achieve arbitrary code execution. The vulnerability's presence in widely deployed software versions makes it particularly attractive to threat actors seeking to compromise user systems through social engineering campaigns that deliver malicious HTML content via email or web pages.
Mitigation strategies for this vulnerability include immediate application of Microsoft security patches that address the specific HTML parsing flaws in the affected Internet Explorer versions. System administrators should prioritize updating all affected systems to the latest security patches and consider implementing additional protective measures such as email filtering rules that block HTML content from untrusted sources. The ATT&CK framework categorizes this vulnerability under T1203 as Exploitation for Client Execution, where attackers leverage client-side vulnerabilities to achieve their objectives. Organizations should also implement network-based protections including web application firewalls and content filtering systems to prevent delivery of malicious HTML content to user systems. Regular security assessments and vulnerability scanning should be conducted to ensure that all systems remain protected against similar rendering flaws that may be discovered in the future.