CVE-2012-1966 in Firefox
Summary
by MITRE
Mozilla Firefox 4.x through 13.0 and Firefox ESR 10.x before 10.0.6 do not have the same context-menu restrictions for data: URLs as for javascript: URLs, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a crafted URL.
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Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2012-1966 represents a significant security flaw in Mozilla Firefox versions ranging from 4.x through 13.0 and Firefox ESR 10.x before 10.0.6. This issue stems from inconsistent handling of context-menu restrictions between different URL schemes, specifically data: URLs and javascript: URLs. The flaw creates a dangerous discrepancy in how Firefox processes these two distinct URL types, leading to potential cross-site scripting attacks that could compromise user security and data integrity.
The technical root cause of this vulnerability lies in Firefox's implementation of URL scheme handling within its context menu system. When users interact with web content, Firefox should apply consistent security policies regardless of whether a URL uses the data: scheme or javascript: scheme. However, the browser failed to enforce identical restrictions for these two URL types, creating a potential attack vector for malicious actors. The data: URL scheme allows embedding of arbitrary data directly within the URL, while javascript: URLs execute JavaScript code when loaded. The inconsistency in how these schemes are treated in the context menu allows attackers to exploit this gap and bypass intended security controls.
This vulnerability enables remote attackers to conduct cross-site scripting attacks by crafting malicious URLs that exploit the inconsistent context-menu restrictions. When users interact with web content containing such crafted URLs, the browser's inconsistent handling of data: URLs versus javascript: URLs can result in unauthorized script execution. The attack surface is particularly concerning because context menus are frequently accessed by users during normal browsing activities, making this vulnerability particularly dangerous. An attacker could embed malicious data: URLs within web pages that, when accessed through context menus, would execute unauthorized code in the victim's browser session.
The operational impact of this vulnerability extends beyond simple XSS attacks, potentially allowing attackers to steal session cookies, modify page content, redirect users to malicious sites, or perform actions on behalf of the user. This flaw particularly affects users of older Firefox versions where the security patch has not yet been applied. The vulnerability's persistence across multiple Firefox versions demonstrates the complexity of addressing such context-menu related security issues and highlights the importance of maintaining up-to-date browser software. Organizations and individual users who rely on Firefox for web browsing must be aware of this vulnerability and apply patches promptly.
Security mitigations for this vulnerability primarily involve updating to patched versions of Firefox where the inconsistent URL scheme handling has been corrected. Mozilla released updates addressing this specific flaw in Firefox ESR 10.0.6 and subsequent versions. System administrators should ensure all Firefox installations are updated to versions that contain the appropriate security patches. Additionally, users should be educated about the risks of interacting with untrusted content and should avoid clicking on suspicious links or context menu options. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and relates to ATT&CK technique T1059.007 for script-based attacks. Organizations should implement comprehensive patch management processes to address similar context-menu related vulnerabilities and maintain awareness of browser security updates.