CVE-2012-1961 in Firefox
Summary
by MITRE
Mozilla Firefox 4.x through 13.0, Firefox ESR 10.x before 10.0.6, Thunderbird 5.0 through 13.0, Thunderbird ESR 10.x before 10.0.6, and SeaMonkey before 2.11 do not properly handle duplicate values in X-Frame-Options headers, which makes it easier for remote attackers to conduct clickjacking attacks via a FRAME element referencing a web site that produces these duplicate values.
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Analysis
by VulDB Data Team • 10/21/2024
This vulnerability resides in the web browser security mechanisms of Mozilla Firefox and Thunderbird applications, specifically targeting how these browsers process X-Frame-Options headers. The flaw exists in versions ranging from Firefox 4.x through 13.0, Firefox ESR 10.x before 10.0.6, Thunderbird 5.0 through 13.0, Thunderbird ESR 10.x before 10.0.6, and SeaMonkey before 2.11. The core issue involves the improper handling of duplicate X-Frame-Options header values, which creates a security weakness that can be exploited by remote attackers to bypass intended clickjacking protections. When a web page contains duplicate X-Frame-Options headers, the vulnerable browsers fail to properly interpret these duplicate values, potentially allowing malicious actors to inject FRAME elements that could deceive users into interacting with unintended content.
The technical implementation of this vulnerability stems from the browser's header processing logic where duplicate X-Frame-Options values are not consistently evaluated. According to CWE-16, this represents a weakness in the design or implementation of security controls, specifically in how HTTP headers are parsed and validated. The X-Frame-Options header is a security feature designed to prevent clickjacking attacks by controlling whether a browser should allow a page to be displayed in a FRAME or IFRAME. When duplicate values exist, the browser's security mechanism fails to properly enforce the intended protection, creating an attack surface that malicious actors can exploit. This behavior violates the principle of least privilege and fails to maintain proper security boundaries between different web content contexts.
The operational impact of this vulnerability is significant as it directly enables sophisticated clickjacking attacks that can deceive users into performing unintended actions. Attackers can craft malicious web pages that include FRAME elements referencing vulnerable sites with duplicate X-Frame-Options headers, potentially leading to user interface redressing attacks where legitimate users are tricked into interacting with malicious content. This vulnerability aligns with ATT&CK technique T1203, which describes user execution through malicious content, and T1566, which covers credential access through phishing. The attack vector allows for the manipulation of user interactions and can potentially lead to session hijacking, data theft, or other malicious activities that compromise user security and privacy.
Organizations and users affected by this vulnerability should immediately update to patched versions of their software, as the fix typically involves proper handling of duplicate HTTP headers in the browser's security implementation. The recommended mitigation strategy includes applying security patches promptly, implementing additional security controls such as Content Security Policy headers, and monitoring for suspicious web content. System administrators should also consider deploying web application firewalls that can detect and block malicious FRAME injection attempts, while users should exercise caution when visiting untrusted websites. This vulnerability demonstrates the importance of proper HTTP header validation and the need for comprehensive security testing of web browser implementations to prevent such bypasses of fundamental security protections. The fix typically involves ensuring that duplicate header values are properly processed and that the most restrictive security policy is enforced regardless of header duplication, aligning with security best practices outlined in NIST SP 800-53 and OWASP security guidelines.