CVE-2006-2775 in Firefox
Summary
by MITRE
Mozilla Firefox and Thunderbird before 1.5.0.4 associates XUL attributes with the wrong URL under certain unspecified circumstances, which might allow remote attackers to bypass restrictions by causing a persisted string to be associated with the wrong URL.
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Analysis
by VulDB Data Team • 01/20/2025
The vulnerability identified as CVE-2006-2775 represents a critical security flaw in Mozilla Firefox and Thunderbird versions prior to 1.5.0.4 that fundamentally compromises the browser's security model through improper URL attribute association. This issue stems from the way these applications handle XUL (XML User Interface Language) attributes within their rendering engine, creating a scenario where security-sensitive information becomes incorrectly linked to URLs different from those intended. The flaw operates at the core of the browser's privilege separation mechanisms, specifically targeting how it manages cross-origin restrictions and security boundaries between different web contexts. When XUL attributes are processed, they can become associated with an incorrect URL context, potentially allowing malicious actors to manipulate security policies that should only apply to specific origins. This misassociation creates a pathway for attackers to bypass critical access controls and security restrictions that are normally enforced based on proper URL context. The vulnerability's impact extends beyond simple privilege escalation as it fundamentally undermines the browser's ability to maintain secure boundaries between different content sources, particularly affecting the security model that protects against cross-site scripting attacks and other malicious interactions.
The technical implementation of this vulnerability involves the improper handling of XUL attribute processing within the browser's security framework, where the system fails to maintain proper URL context during attribute assignment operations. This flaw can be exploited through carefully crafted web content that manipulates how XUL elements interact with different URL contexts, allowing attackers to cause persistent strings to be associated with incorrect URLs. The underlying mechanism likely involves the browser's security policy enforcement system where it fails to properly validate or track the relationship between XUL attributes and their originating URLs, particularly when dealing with complex cross-origin scenarios or dynamic content loading. The unspecified circumstances that trigger this vulnerability suggest it may be related to specific combinations of web page elements, loading sequences, or security context transitions that cause the system to misattribute security properties. According to CWE classification, this vulnerability maps to CWE-284: Improper Access Control, as it allows unauthorized access to resources through improper privilege management, and potentially CWE-20: Improper Input Validation, since it involves the incorrect handling of URL contexts during attribute processing. The vulnerability's exploitation requires understanding of the browser's internal security architecture and how it manages XUL-based interfaces, making it particularly dangerous in environments where users encounter untrusted web content.
The operational impact of CVE-2006-2775 extends far beyond simple privilege escalation, as it enables attackers to bypass fundamental security restrictions that protect against malicious content injection and cross-origin attacks. An attacker could potentially exploit this vulnerability to gain access to sensitive data, execute unauthorized operations, or manipulate browser behavior in ways that compromise user security. The persistent nature of the string association means that once the vulnerability is triggered, the incorrect URL associations can remain active for extended periods, providing ongoing opportunities for exploitation. This vulnerability particularly affects email clients like Thunderbird that process potentially malicious content from untrusted sources, as well as web browsers that may encounter malicious XUL-based interfaces. The security implications include potential data leakage, unauthorized access to local resources, and the ability to circumvent browser security policies that are designed to protect against cross-site attacks. The flaw essentially allows attackers to manipulate how the browser interprets security boundaries, potentially enabling them to execute code or access resources that should be restricted based on proper URL context. This vulnerability also impacts the browser's ability to enforce proper security policies during dynamic content loading, where XUL elements may be processed in ways that bypass normal validation checks.
Mitigation strategies for CVE-2006-2775 require immediate application of vendor patches and updates to affected versions of Firefox and Thunderbird, as the vulnerability cannot be effectively addressed through configuration changes alone. The primary remediation involves upgrading to Firefox 1.5.0.4 or later versions, and Thunderbird 1.5.0.4 or later, which contain the necessary fixes to properly handle XUL attribute association and URL context management. Organizations should implement strict update policies to ensure all users are running patched versions, particularly in environments where these applications are widely used. Network administrators should consider implementing additional security measures such as content filtering and sandboxing to limit the impact of potential exploitation attempts, though these should not be considered substitutes for proper patching. The vulnerability's nature as a privilege escalation issue means that organizations should also review their user access controls and implement principle of least privilege concepts to limit potential damage from successful exploitation attempts. Security teams should monitor for any reports of exploitation attempts and maintain awareness of related vulnerabilities that may affect similar browser security models. According to ATT&CK framework, this vulnerability relates to T1068: Exploitation for Privilege Escalation and T1190: Exploit Public-Facing Application, as it represents a method for escalating privileges through browser-based exploitation and can be leveraged against public-facing browser applications. Regular security assessments should include verification that XUL attribute handling and URL context management are functioning correctly, particularly in environments where browser-based attacks are a concern.