CVE-2017-5394 in Firefox
Summary
by MITRE
A location bar spoofing attack where the location bar of loaded page will be shown over the content of another tab due to a series of JavaScript events combined with fullscreen mode. Note: This issue only affects Firefox for Android. Other operating systems are not affected. This vulnerability affects Firefox < 51.
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Analysis
by VulDB Data Team • 08/27/2024
This vulnerability represents a sophisticated location bar spoofing attack that exploits a specific interaction between JavaScript event handling and fullscreen mode in Firefox for Android. The flaw occurs when a malicious website can manipulate the browser's interface to display its own location bar over the content of another active tab, creating a deceptive user experience that could facilitate phishing attacks or other social engineering schemes. The vulnerability specifically targets the Android implementation of Firefox, leaving other operating systems unaffected, which suggests a platform-specific implementation issue rather than a fundamental browser architecture flaw. The security implications are particularly concerning given that this attack can occur during normal browsing sessions when users navigate between multiple tabs, potentially exposing them to fraudulent websites without their knowledge. This type of attack falls under the category of user interface deception techniques that can bypass traditional security measures by exploiting the visual presentation layer rather than underlying system vulnerabilities.
The technical execution of this vulnerability relies on a sequence of JavaScript events that manipulate the browser's fullscreen API in combination with specific timing and rendering behaviors within Firefox's Android implementation. When a website enters fullscreen mode and subsequently triggers a series of JavaScript events, it can cause the browser to render its own location bar interface over content from other tabs, effectively obscuring the legitimate webpage content. This behavior stems from how Firefox for Android handles the transition between fullscreen and normal display modes, particularly when multiple tabs are active and the browser's rendering engine processes events from different contexts simultaneously. The flaw demonstrates a lack of proper isolation between different tab contexts during fullscreen transitions, allowing cross-tab interference that should not normally occur. This type of vulnerability aligns with CWE-611 Improper Restriction of XML External Entity Reference and CWE-200 Information Exposure, as it exposes users to potentially malicious content through interface manipulation rather than direct data leakage.
The operational impact of this vulnerability extends beyond simple visual deception to create significant security risks for Firefox users on Android platforms. Attackers could exploit this flaw to create convincing phishing pages that appear to be legitimate websites, potentially capturing sensitive information such as login credentials, personal data, or financial information. The attack vector is particularly insidious because it requires no special privileges or complex exploitation techniques, relying instead on the browser's normal operation and user trust in the displayed interface. Users may not realize they have been deceived until they attempt to interact with the page, at which point they might unknowingly submit sensitive information to a malicious actor. This vulnerability also demonstrates a failure in browser sandboxing principles and tab isolation mechanisms, as it allows one tab's interface elements to interfere with another tab's content rendering. The attack could be particularly effective in mobile environments where users frequently switch between multiple tabs and may not notice the interface change immediately.
The remediation for this vulnerability required Firefox developers to implement stricter isolation mechanisms between tabs during fullscreen transitions and to enhance the validation of interface rendering behaviors when multiple tabs are active. The fix involved modifying how Firefox for Android handles fullscreen mode transitions and ensuring that tab-specific interface elements cannot interfere with content from other tabs. This type of fix aligns with ATT&CK technique T1056.001 Input Injection: Keylogging, where interface manipulation can be used to deceive users into providing information. The vulnerability highlights the importance of proper context isolation in mobile browser implementations and the need for comprehensive testing of edge cases involving fullscreen mode and tab management. Users should update to Firefox version 51 or later to receive the necessary security patches, while security teams should monitor for similar interface manipulation attacks that could exploit platform-specific implementation details in other mobile browsers. Organizations using Firefox for Android should consider implementing additional user education about interface changes and potential phishing indicators, particularly in environments where mobile security is critical. The vulnerability also underscores the need for continuous security testing of mobile browser implementations, as platform-specific features often introduce unique attack surfaces that may not be apparent in desktop environments.