CVE-2016-9065 in Firefox
Summary
by MITRE
The location bar in Firefox for Android can be spoofed by forcing a user into fullscreen mode, blocking its exiting, and creating of a fake location bar without any user notification. Note: This issue only affects Firefox for Android. Other versions and operating systems are unaffected. This vulnerability affects Firefox < 50.
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Analysis
by VulDB Data Team • 10/04/2022
This vulnerability represents a sophisticated user interface spoofing attack that specifically targets Firefox for Android users. The flaw exploits the browser's handling of fullscreen mode and location bar display, creating a deceptive environment where users cannot distinguish between legitimate and malicious web content. The vulnerability is classified under CWE-601 as URL Redirector Abuse, where an application fails to properly validate or display URLs, allowing attackers to manipulate user perception of web addresses. This issue falls within the ATT&CK framework under T1056 as a form of input injection that manipulates user interface elements to deceive users into trusting malicious content. The vulnerability specifically affects Firefox versions prior to 50, making it a critical concern for users who have not updated their browsers.
The technical implementation of this exploit involves forcing the browser into fullscreen mode while simultaneously blocking user exit mechanisms from this mode. This creates a scenario where the browser's normal location bar display is obstructed or replaced with a fake interface element. Attackers can then overlay a convincing but false location bar that displays misleading URL information without alerting the user to the deception. The vulnerability leverages the Android browser's fullscreen API and user interface rendering mechanisms to create an environment where legitimate browser functionality is obscured or manipulated. The lack of user notification about the spoofed interface element makes this particularly dangerous as users cannot verify the authenticity of displayed URLs or browser state.
The operational impact of this vulnerability extends beyond simple phishing attacks to potentially enable more sophisticated social engineering campaigns. Users who encounter this spoofing attack may unknowingly enter sensitive information on fake websites that appear to be legitimate. The vulnerability essentially removes the user's ability to verify the actual website address, which is a fundamental security control in web browsing. This attack vector could be particularly effective in credential harvesting scenarios where attackers create fake login pages that appear authentic due to the spoofed location bar. The vulnerability demonstrates a failure in browser security model implementation where the user interface itself becomes a point of compromise rather than a protective element.
Mitigation strategies for this vulnerability include immediate browser updates to Firefox version 50 or later, which contain fixes for the fullscreen mode handling and location bar display issues. Users should also implement additional security measures such as enabling browser security warnings for mixed content and regularly updating their devices to ensure they have the latest security patches. Organizations should consider implementing browser security policies that mandate regular updates and educate users about recognizing potential spoofing attempts. The fix implemented in Firefox 50 addresses the core issue by improving the handling of fullscreen mode transitions and ensuring that location bar information remains accessible and verifiable even when fullscreen mode is active. This vulnerability highlights the importance of maintaining current browser versions and the critical role that user interface security plays in overall web security posture.