CVE-2024-7518 in Firefox
Summary
by MITRE • 08/06/2024
Select options could obscure the fullscreen notification dialog. This could be used by a malicious site to perform a spoofing attack. This vulnerability affects Firefox < 129 and Firefox ESR < 128.1.
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Analysis
by VulDB Data Team • 03/15/2025
This vulnerability in Firefox represents a sophisticated user interface deception mechanism that exploits the browser's handling of select elements and fullscreen notifications. The flaw allows malicious websites to manipulate the visual hierarchy of browser interfaces, creating conditions where standard security warnings and notifications become obscured or inaccessible to users. This type of attack falls under the broader category of user interface redressing and can be classified as a CWE-691 weakness, specifically involving insufficient control of a resource through a mechanism that allows access to restricted information or functionality. The vulnerability stems from how Firefox manages the z-index and rendering priorities between interactive form elements and system-level notifications, creating a scenario where attacker-controlled select options can be positioned to overlay or hide critical security alerts.
The technical implementation of this vulnerability relies on the browser's rendering engine behavior when processing fullscreen API interactions combined with HTML select element positioning. When a website triggers a fullscreen notification dialog while simultaneously manipulating select options, the browser's default layering mechanism can be disrupted. This creates a window where malicious actors can position their own interface elements to obscure legitimate security warnings, potentially leading users to unknowingly interact with compromised content or provide sensitive information. The vulnerability specifically impacts Firefox versions prior to 129 and Firefox ESR versions prior to 128.1, indicating that the underlying rendering and layer management systems were not properly accounting for the potential for such visual conflicts. This issue aligns with ATT&CK technique T1566.001, which involves social engineering through deceptive interfaces, and represents a critical gap in browser security model implementation where user interface elements can be weaponized for malicious purposes.
The operational impact of this vulnerability extends beyond simple visual obfuscation to encompass significant security risks for end users. Attackers could exploit this weakness to mask phishing attempts, malicious download prompts, or other critical security warnings, effectively bypassing user awareness mechanisms that are fundamental to browser security. The spoofing capability allows for sophisticated deception attacks where users may be tricked into performing actions they would normally avoid, as the legitimate security notifications become inaccessible or hidden. This vulnerability particularly affects scenarios where users are engaged in sensitive activities such as financial transactions, account management, or data entry, where the presence of clear security warnings is crucial for maintaining user protection. The risk is amplified because the attack requires no special privileges or complex exploitation techniques beyond standard web page manipulation, making it accessible to attackers with basic web development knowledge. Organizations relying on Firefox for security-sensitive operations should consider this vulnerability as a potential vector for social engineering attacks that could bypass traditional security controls and user education efforts.