CVE-2003-0594 in Mozilla
Summary
by MITRE
Mozilla allows remote attackers to bypass intended cookie access restrictions on a web application via "%2e%2e" (encoded dot dot) directory traversal sequences in a URL, which causes Mozilla to send the cookie outside the specified URL subsets, e.g. to a vulnerable application that runs on the same server as the target application.
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Analysis
by VulDB Data Team • 06/29/2021
This vulnerability exists in the mozilla web browser implementation of url handling and cookie management protocols. The flaw stems from improper validation of directory traversal sequences in url parsing where the encoded dot dot sequences "%2e%2e" are not properly sanitized or rejected during url processing. When a malicious user crafts a url containing these sequences, the browser fails to correctly interpret the intended path traversal and instead processes the cookie information in a manner that violates the original security boundaries established by the web application.
The technical execution of this vulnerability relies on the browser's failure to properly resolve relative paths when directory traversal sequences are present in the url. When mozilla encounters a url containing "%2e%2e" sequences, it does not correctly normalize the path to prevent access beyond the intended directory boundaries. This allows cookies that should be restricted to specific application paths to be transmitted to unintended locations on the same server. The vulnerability operates at the intersection of web application security and browser implementation, specifically targeting the cookie access control mechanisms that are fundamental to web application security.
The operational impact of this vulnerability is significant as it enables attackers to bypass the same-site cookie restrictions that are designed to prevent cross-site cookie theft. An attacker can craft malicious urls that cause the browser to send cookies intended for one application to another application running on the same server, effectively allowing cookie theft across application boundaries. This creates a serious security risk particularly when applications share the same server but should maintain separate security contexts. The vulnerability is classified under cwe-22 directory traversal and cwe-352 cross-site request forgery, representing a fundamental breakdown in the browser's url parsing and cookie handling security controls.
The attack vector requires an attacker to have knowledge of the target server's application structure and be able to craft malicious urls that exploit this path traversal behavior. This vulnerability is particularly dangerous in environments where multiple applications share the same server and rely on cookie-based session management. The impact extends beyond simple cookie theft to potentially enable session hijacking, privilege escalation, and data exposure attacks. Security practitioners should note that this vulnerability highlights the importance of proper url normalization and path resolution in web browser implementations, and demonstrates how seemingly minor parsing issues can lead to significant security breaches. Mitigation strategies should include implementing proper url validation, ensuring that browsers correctly normalize paths, and employing additional security controls such as httponly flags on cookies and proper server-side access controls to reduce the impact of such client-side vulnerabilities.