CVE-2003-0114 in Internet Explorer
Summary
by MITRE
The file upload control in Microsoft Internet Explorer 5.01, 5.5, and 6.0 allows remote attackers to automatically upload files from the local system via a web page containing a script to upload the files.
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Analysis
by VulDB Data Team • 03/08/2021
This vulnerability resides in the file upload functionality of Microsoft Internet Explorer versions 5.01, 5.5, and 6.0, representing a critical security flaw that enables remote code execution through automated file transfers. The vulnerability stems from insufficient validation mechanisms within the browser's file upload control, which fails to properly sanitize or restrict file operations initiated through web-based scripts. Attackers can craft malicious web pages containing embedded scripts that automatically trigger file uploads from the victim's local system without explicit user consent or awareness. This represents a classic cross-site scripting attack vector combined with unauthorized file manipulation capabilities.
The technical exploitation occurs through the manipulation of the browser's file input elements and associated scripting interfaces. When a user visits a malicious webpage containing crafted javascript code, the script can programmatically access the file upload control and force the browser to upload files from predetermined locations on the local filesystem. This flaw operates at the browser level rather than requiring system-level privileges, making it particularly dangerous as it can be exploited through simple web browsing activities. The vulnerability specifically targets the client-side file handling mechanisms and leverages the browser's trust relationship with local file systems.
The operational impact of this vulnerability extends beyond simple unauthorized file transfers, as it can enable attackers to exfiltrate sensitive data, deploy malicious payloads, or establish persistent access points on compromised systems. The automatic nature of the upload process means victims do not need to interact with malicious content beyond visiting the compromised webpage, making detection and prevention particularly challenging. This vulnerability aligns with CWE-434 which describes insecure file upload vulnerabilities where applications fail to validate or restrict file types and locations during upload operations. The attack pattern corresponds to techniques described in the ATT&CK framework under T1195 for Phishing with Malicious Attachments and T1059 for Command and Scripting Interpreter.
Mitigation strategies must address both the immediate browser-level vulnerability and broader security practices. Microsoft released patches for affected Internet Explorer versions to correct the file upload validation logic, requiring users to update their browsers immediately. Network administrators should implement web content filtering solutions that can detect and block malicious file upload scripts, while also deploying endpoint protection measures that monitor for suspicious file transfer activities. Users should be educated about the dangers of visiting untrusted websites and the importance of keeping browsers updated. The vulnerability also highlights the need for proper input validation and secure coding practices, particularly around file handling operations, as recommended by the OWASP Top Ten and other security standards. Organizations should consider implementing browser hardening policies that restrict automatic file operations and disable unnecessary scripting capabilities that could be exploited in similar vulnerabilities.