CVE-2005-2455 in Greasemonkey
Summary
by MITRE
Greasemonkey before 0.3.5 allows remote web servers to (1) read arbitrary files via a GET request to a file:// URL in the GM_xmlhttpRequest API function, (2) list installed scripts using GM_scripts, or obtain sensitive information via (3) GM_setValue and GM_getValue.
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Analysis
by VulDB Data Team • 11/22/2024
The vulnerability described in CVE-2005-2455 represents a critical security flaw in the Greasemonkey browser extension version 0.3.4 and earlier. This issue stems from insufficient input validation and access control mechanisms within the extension's core API functions, specifically affecting the GM_xmlhttpRequest, GM_scripts, GM_setValue, and GM_getValue functions. The vulnerability exists in the context of browser-based extension security models where user scripts execute with elevated privileges but should remain isolated from system resources and other scripts. The flaw allows malicious remote web servers to exploit these functions and gain unauthorized access to local system resources, fundamentally undermining the security boundaries that separate browser extensions from underlying operating system components.
The technical implementation of this vulnerability relies on the improper handling of file:// URLs within the GM_xmlhttpRequest API function. When a remote server crafts a malicious GET request to a file:// URL, the extension fails to validate or restrict such requests, enabling direct file system access. This represents a classic case of insufficient input sanitization and access control enforcement, with the vulnerability mapping to CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and CWE-20 (Improper Input Validation). Additionally, the GM_scripts function lacks proper authorization checks, allowing attackers to enumerate installed scripts and potentially discover sensitive information about the user's extension environment. The GM_setValue and GM_getValue functions suffer from inadequate access controls that permit unauthorized information disclosure, creating a data exposure scenario that aligns with CWE-200 (Information Exposure) and CWE-502 (Deserialization of Untrusted Data).
The operational impact of this vulnerability is severe and multifaceted, affecting both user privacy and system integrity. Remote attackers can leverage these weaknesses to read arbitrary files from the victim's local system, potentially accessing sensitive information such as configuration files, personal documents, or even credentials stored in browser caches. The script enumeration capability through GM_scripts provides attackers with intelligence about the user's browser extension environment, enabling more sophisticated targeting attacks. The information disclosure through GM_setValue and GM_getValue functions can reveal user preferences, session data, or other sensitive configuration information. This vulnerability effectively transforms the browser extension environment from a secure sandbox into a potential attack vector for local file system exploitation, with implications for both individual user security and enterprise security posture.
Mitigation strategies for CVE-2005-2455 require immediate action through software updates and implementation of proper access control measures. The primary remediation involves upgrading to Greasemonkey version 0.3.5 or later, where the developers implemented proper input validation and access restriction mechanisms for all affected API functions. Organizations should also implement browser extension security policies that limit the capabilities of third-party extensions and monitor for suspicious extension behavior. The vulnerability highlights the importance of proper API design principles, specifically the need for input validation, access control enforcement, and proper sandboxing of extension code execution. Security professionals should consider implementing network monitoring to detect unauthorized file access attempts and ensure that browser extensions are regularly updated to address known vulnerabilities. This case demonstrates the critical need for maintaining up-to-date security practices in browser extension ecosystems and serves as a reminder of the potential consequences of inadequate access control implementation in privileged code execution environments. The vulnerability also underscores the relevance of ATT&CK technique T1059.007 (Command and Scripting Interpreter: JavaScript) and T1074.001 (Data Staged: Local Data Staging) in threat modeling for browser-based attack vectors.