CVE-2001-0089 in Internet Explorer
Summary
by MITRE
Internet Explorer 5.0 through 5.5 allows remote attackers to read arbitrary files from the client via the INPUT TYPE element in an HTML form, aka the "File Upload via Form" vulnerability.
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Analysis
by VulDB Data Team • 03/22/2025
The vulnerability described in CVE-2001-0089 represents a critical security flaw in Microsoft Internet Explorer versions 5.0 through 5.5 that enables remote attackers to perform unauthorized file access operations on client systems. This vulnerability specifically targets the INPUT TYPE element within HTML forms, creating a pathway for malicious actors to exploit the browser's handling of file upload mechanisms. The flaw fundamentally undermines the security boundaries that should exist between web applications and local client file systems, allowing attackers to bypass normal file access restrictions that are typically enforced by operating system security models.
The technical implementation of this vulnerability exploits the way Internet Explorer processes HTML form elements, particularly those related to file input fields. When a web page contains an INPUT element with type="file", the browser normally presents a file selection dialog to users for legitimate file upload purposes. However, this particular vulnerability allows attackers to manipulate the form processing behavior to read arbitrary files from the victim's local system without proper authorization. The flaw stems from insufficient validation and sanitization of file path parameters within the HTML form handling code, creating a direct pathway for path traversal attacks that can access files outside the intended upload directories.
The operational impact of CVE-2001-0089 extends far beyond simple information disclosure, as it provides attackers with the capability to access sensitive files that may contain personal data, system configurations, or application credentials. This vulnerability can be exploited in various attack scenarios including phishing campaigns, where attackers craft malicious web pages that automatically attempt to access and exfiltrate files from compromised systems. The attack vector is particularly dangerous because it requires no special privileges or complex exploitation techniques, making it accessible to attackers with minimal technical expertise. This vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and represents a classic example of how browser-based vulnerabilities can be leveraged to compromise client-side security.
From an attack framework perspective, this vulnerability maps directly to several MITRE ATT&CK techniques including T1059 for command and scripting interpreter and T1566 for phishing with social engineering. The vulnerability's exploitation typically involves crafting malicious HTML content that contains specially formatted INPUT elements designed to trigger the file access behavior. Security professionals should note that this vulnerability existed during a period when web browser security was less mature, and the lack of proper input validation in the browser's HTML parser created a significant attack surface. The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in web browser implementations, where client-side applications should never be trusted to handle file system operations without proper sandboxing and access controls.
Mitigation strategies for CVE-2001-0089 primarily involve upgrading to newer versions of Internet Explorer where this vulnerability has been patched, as well as implementing network-level protections such as web application firewalls that can detect and block malicious HTML content. Organizations should also consider implementing browser security policies that restrict file access capabilities, though such measures are limited in effectiveness against this particular vulnerability. The recommended remediation includes comprehensive browser updates, deployment of security patches, and implementation of proper content filtering mechanisms to prevent the delivery of malicious HTML content that could exploit this vulnerability. Additionally, user education regarding the risks of visiting untrusted websites and the importance of keeping browsers updated remains critical in defending against such client-side attacks that leverage browser implementation flaws.