CVE-2002-1291 in Java Virtual Machine
Summary
by MITRE
The Microsoft Java implementation, as used in Internet Explorer, allows remote attackers to read arbitrary local files and network shares via an applet tag with a codebase set to a "file://%00" (null character) URL.
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Analysis
by VulDB Data Team • 05/25/2019
The vulnerability described in CVE-2002-1291 represents a critical security flaw in Microsoft's Java Runtime Environment implementation within Internet Explorer. This issue stems from improper input validation and path handling mechanisms that allow malicious actors to exploit a weakness in how the browser processes applet tags with specific codebase parameters. The vulnerability specifically targets the way the Java Virtual Machine handles file URLs containing null characters, creating a pathway for unauthorized file access that extends beyond normal security boundaries. This flaw exists in the context of Microsoft's attempt to provide Java applet support within the Windows Internet Explorer browser environment, where the Java plugin component interacts with the operating system's file system through a series of security checks that are bypassed when null characters are present in the URL structure.
The technical exploitation mechanism relies on the manipulation of the codebase attribute within applet tags to point to a malformed URL that includes a null character encoded as %00. When Internet Explorer processes this malformed URL, the Java implementation fails to properly sanitize the input, allowing the applet to access local file systems and network shares without proper authentication or authorization. The null character injection technique bypasses standard file path validation routines that would normally reject such malformed inputs, enabling attackers to traverse file system boundaries and access sensitive files on the target system. This vulnerability operates at the intersection of web browser security and Java applet execution, where the Java plugin's security model is effectively circumvented through the manipulation of URL parsing and path resolution mechanisms.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with the capability to read arbitrary local files and access network shares from systems running vulnerable versions of Internet Explorer. An attacker could potentially extract sensitive information including configuration files, user credentials, system logs, and other confidential data stored on the local machine or accessible through network shares. The vulnerability affects not only individual user systems but also corporate environments where multiple users may be running vulnerable versions of Internet Explorer, potentially allowing lateral movement and privilege escalation within network boundaries. This type of vulnerability directly impacts the principle of least privilege and can be leveraged to establish persistent access to systems, making it particularly dangerous in enterprise environments where network security is paramount.
The vulnerability maps directly to CWE-22 - Improper Limitation of a Pathname to a Restricted Directory and CWE-77 - Improper Neutralization of Special Elements used in a Command. From an ATT&CK perspective, this vulnerability aligns with T1059 - Command and Scripting Interpreter and T1083 - File and Directory Discovery, as it enables attackers to execute commands through manipulated Java applets and discover file system contents. Organizations should implement immediate mitigations including disabling Java applet support in Internet Explorer, applying security patches from Microsoft, and configuring network firewalls to block access to potentially malicious URLs. Additionally, regular security assessments should be conducted to identify and remediate similar vulnerabilities in other components of the web browser ecosystem, as this type of path traversal vulnerability continues to be a significant concern in web application security. The incident highlights the importance of robust input validation and the need for comprehensive security testing of integrated components within complex software environments.