CVE-2002-2314 in Mozilla
Summary
by MITRE
Mozilla 1.0 allows remote attackers to steal cookies from other domains via a javascript: URL with a leading "//" and ending in a newline, which causes the host/path check to fail.
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Analysis
by VulDB Data Team • 12/27/2024
This vulnerability resides in the Mozilla 1.0 web browser's handling of javascript: URLs and demonstrates a classic cross-site scripting attack vector through improper URL parsing. The flaw occurs when a malicious attacker crafts a javascript: URL that begins with a double forward slash followed by a newline character, which bypasses the browser's domain validation checks. This specific construction exploits a weakness in how Mozilla processes URL schemes and host verification mechanisms, allowing an attacker to inject malicious JavaScript code that can execute in the context of a different domain.
The technical implementation of this vulnerability stems from the browser's inadequate validation of javascript: URLs that contain leading whitespace characters and newline sequences. When Mozilla encounters a javascript: URL with the specific pattern of leading "//" followed by a newline, the URL parsing logic fails to properly extract and validate the host component of the URL. This parsing failure creates a condition where the browser treats the malicious URL as if it originated from the current domain, thereby bypassing the same-origin policy that normally protects against cookie theft and cross-domain data access. The vulnerability is particularly dangerous because it leverages the browser's trust in URL schemes and fails to properly sanitize input before executing JavaScript code.
The operational impact of this vulnerability extends beyond simple cookie theft to encompass a broader range of session hijacking and data exfiltration attacks. Attackers can leverage this flaw to steal authentication cookies, session tokens, and other sensitive information from users visiting compromised web pages. The vulnerability creates a persistent threat vector that can be exploited across different domains, making it particularly dangerous in environments where users navigate between multiple trusted sites. Security researchers have classified this as a privilege escalation issue since it allows attackers to perform actions that should be restricted to the originating domain. The attack requires minimal user interaction beyond visiting a malicious page, making it particularly effective for social engineering campaigns.
Mitigation strategies for this vulnerability involve implementing proper URL parsing and validation mechanisms within the browser's JavaScript execution environment. Security patches should enforce strict URL scheme validation that rejects malformed URLs containing leading whitespace or special characters that could bypass domain checks. The fix should include comprehensive input sanitization that normalizes URL formats before processing, ensuring that all URL components are properly extracted and validated against the expected domain. Organizations should also implement content security policies that restrict the execution of inline JavaScript and enforce proper cross-origin resource sharing controls. This vulnerability aligns with CWE-20 Improper Input Validation and maps to ATT&CK technique T1059.007 for JavaScript execution, highlighting the need for robust input validation and proper URL handling in web browsers to prevent such cross-domain privilege escalation attacks.