CVE-2015-7185 in Firefox
Summary
by MITRE
Mozilla Firefox before 42.0 on Android does not ensure that the address bar is restored upon fullscreen-mode exit, which allows remote attackers to spoof the address bar via crafted JavaScript code.
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Analysis
by VulDB Data Team • 06/26/2022
The vulnerability identified as CVE-2015-7185 affects Mozilla Firefox versions prior to 42.0 on Android platforms, representing a critical security flaw in the browser's user interface handling during fullscreen mode transitions. This issue stems from insufficient validation mechanisms that fail to properly restore the address bar display state when exiting fullscreen mode, creating a potential vector for sophisticated phishing attacks and user deception. The flaw specifically manifests in the Android implementation of Firefox, where the browser's security model does not adequately enforce address bar visibility constraints during fullscreen mode operations, allowing malicious actors to manipulate the user interface in ways that compromise security awareness.
The technical implementation of this vulnerability involves the browser's failure to maintain proper state management between fullscreen and normal display modes. When Firefox enters fullscreen mode, the address bar typically becomes hidden to maximize screen real estate for web content. However, the vulnerability occurs during the exit process where the browser does not reliably restore the address bar to its proper display state. This creates a window of opportunity for attackers to execute crafted JavaScript code that can manipulate the browser interface, potentially displaying fake address bar content that mimics legitimate websites. The flaw operates at the intersection of browser UI rendering and JavaScript execution, where the security boundary between legitimate interface behavior and malicious manipulation becomes blurred.
From an operational impact perspective, this vulnerability exposes users to significant phishing risks and credential theft opportunities. Attackers can exploit the address bar spoofing capability to create convincing fake web pages that appear to be legitimate sites, potentially tricking users into entering sensitive information such as login credentials, financial data, or personal identifiers. The vulnerability is particularly dangerous in mobile environments where users may be less vigilant about address bar verification due to smaller screen sizes and different interaction patterns. Security researchers have classified this issue as a user interface deception vulnerability that undermines the fundamental security principle of maintaining clear visual indicators of site identity and trustworthiness. The attack vector requires only a malicious website that can execute JavaScript code, making it accessible to threat actors with minimal technical expertise.
The remediation approach for this vulnerability involves implementing proper state management protocols during fullscreen mode transitions, ensuring that the address bar is consistently restored to its expected display state regardless of how the user exits fullscreen mode. Browser vendors should implement robust validation mechanisms that verify the integrity of UI elements during mode transitions and maintain proper security boundaries between different display states. This fix aligns with security best practices outlined in the OWASP Mobile Top 10 and addresses the underlying CWE-691 weakness related to insufficient control flow management in user interface elements. Organizations should prioritize updating Firefox installations to version 42.0 or later, as this release includes the necessary patches to prevent the address bar spoofing behavior. Additionally, security teams should monitor for similar UI manipulation vulnerabilities in other browser implementations and consider implementing browser security policies that restrict JavaScript execution in sensitive contexts. The vulnerability demonstrates the importance of maintaining security boundaries even in seemingly benign user interface features and highlights the need for comprehensive testing of state transition behaviors in security-critical applications.