CVE-2003-0809 in Internet Explorer
Summary
by MITRE
Internet Explorer 5.01 through 6.0 does not properly handle object tags returned from a Web server during XML data binding, which allows remote attackers to execute arbitrary code via an HTML e-mail message or web page.
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Analysis
by VulDB Data Team • 03/16/2025
This vulnerability exists in Microsoft Internet Explorer versions 5.01 through 6.0 and represents a critical code execution flaw that exploits improper handling of object tags during XML data binding operations. The vulnerability stems from the browser's failure to properly validate and sanitize object tags that are returned from web servers when processing XML data binding scenarios. When Internet Explorer encounters malformed or specially crafted object tags within XML content, it fails to implement adequate security controls that would prevent the execution of malicious code. This flaw specifically manifests when the browser processes HTML email messages or web pages that contain crafted object tags designed to exploit the XML data binding mechanism.
The technical exploitation occurs through a combination of XML data binding and object tag handling vulnerabilities that create a code execution path for remote attackers. During XML data binding operations, Internet Explorer attempts to process object tags that are part of the XML structure, but the browser's implementation lacks proper input validation and sanitization. This allows attackers to inject malicious code within object tags that gets executed when the browser processes the XML data binding operations. The vulnerability is particularly dangerous because it can be triggered through email messages, making it an effective vector for phishing attacks and social engineering campaigns. The flaw is categorized under CWE-129 as an Improper Validation of Array Index, as the browser fails to properly validate the boundaries of object tag processing within XML data binding contexts.
The operational impact of this vulnerability extends beyond simple code execution to encompass full system compromise capabilities for remote attackers. Once successfully exploited, attackers can execute arbitrary code with the privileges of the user running Internet Explorer, potentially leading to complete system compromise. The vulnerability affects a wide range of users since Internet Explorer 5.01 through 6.0 were widely deployed across enterprise and personal computing environments. The attack vector through email messages makes this particularly dangerous as users may unknowingly trigger the exploit simply by opening malicious email content or visiting compromised web pages. This vulnerability aligns with ATT&CK technique T1566.001 for Phishing and T1059.001 for Command and Scripting Interpreter, as it enables both initial compromise through email and subsequent command execution on compromised systems.
Mitigation strategies for this vulnerability require immediate patching of affected Internet Explorer versions, as Microsoft released security updates to address the XML data binding handling flaw. Organizations should implement email filtering solutions that can detect and block malicious object tags within email content, particularly those that attempt to exploit XML data binding mechanisms. Browser hardening measures including disabling XML data binding features or implementing strict content security policies can provide additional protection layers. Network-based intrusion detection systems should be configured to monitor for patterns associated with this specific vulnerability. Users should be trained to avoid opening suspicious email attachments and to exercise caution when visiting untrusted websites. The vulnerability demonstrates the importance of proper input validation and the dangers of complex data binding mechanisms that do not adequately sanitize user-supplied content, making it a prime example of how XML processing can introduce security risks when not properly secured against malicious inputs.