CVE-2008-5505 in Firefox
Summary
by MITRE
Mozilla Firefox 3.x before 3.0.5 allows remote attackers to bypass intended privacy restrictions by using the persist attribute in an XUL element to create and access data entities that are similar to cookies.
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Analysis
by VulDB Data Team • 08/03/2021
This vulnerability resides in mozilla firefox version 3.x prior to 3.0.5 and represents a significant bypass of intended privacy protections through manipulation of xul elements. The flaw specifically leverages the persist attribute functionality within xul markup language which is designed to maintain state information across page reloads. When an attacker crafts malicious xul content with the persist attribute, they can create data entities that behave similarly to browser cookies but operate outside the normal cookie security boundaries. This allows unauthorized access to sensitive information that should normally be restricted by firefox's privacy mechanisms.
The technical implementation exploits the underlying xul persistence system which was intended to provide state management for user interface elements but inadvertently created a pathway for persistent data storage that bypassed standard cookie restrictions. The persist attribute in xul elements enables the storage of data in a manner that persists across sessions, effectively creating a mechanism that could store and retrieve information without the normal security checks that apply to traditional cookies. This creates a vector where malicious content can establish persistent storage that maintains access to user data beyond typical session boundaries.
The operational impact of this vulnerability is substantial as it allows remote attackers to circumvent firefox's intended privacy controls and access data that should remain protected. Attackers can leverage this flaw to create persistent storage mechanisms that maintain access to user information across browsing sessions, potentially enabling tracking of user behavior, session hijacking, or access to sensitive data that was intended to be isolated from unauthorized access. The vulnerability essentially creates a backdoor mechanism for persistent data storage that operates outside the normal cookie security model and browser privacy controls.
This vulnerability aligns with CWE-200, which covers information exposure, and represents a failure in proper access control mechanisms. The flaw demonstrates a weakness in the browser's implementation of privacy controls where the persistence system was not properly isolated from user data access restrictions. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and persistence mechanisms, specifically targeting the browser's user data protection systems. The attack vector requires remote code execution through malicious web content and can be classified under initial access and persistence categories.
Mitigation strategies include updating to firefox 3.0.5 or later versions where this vulnerability has been addressed through proper isolation of the xul persistence mechanisms from cookie-like access patterns. Browser vendors should implement stricter controls over xul element attributes to prevent unauthorized data persistence operations. Additionally, implementing content security policies that restrict the use of potentially dangerous xul attributes can provide defense in depth. Organizations should also consider monitoring for unusual xul persistence patterns in web applications and implementing proper access controls for browser extensions that may interact with xul elements. The fix implemented by mozilla involved tightening the security boundaries around xul element persistence functionality to ensure that the persist attribute cannot be used to create unauthorized cookie-like storage mechanisms.