CVE-2025-0440 in Chrome
Summary
by MITRE • 01/15/2025
Inappropriate implementation in Fullscreen in Google Chrome on Windows prior to 132.0.6834.83 allowed a remote attacker to perform UI spoofing via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 03/19/2025
This vulnerability represents a critical UI spoofing flaw in Google Chrome's fullscreen implementation on Windows platforms, affecting versions prior to 132.0.6834.83. The issue stems from an inadequate validation mechanism that fails to properly sanitize or verify the legitimacy of fullscreen requests originating from malicious web pages. When users encounter a crafted HTML page, the browser's fullscreen mode can be manipulated to display misleading interfaces that appear to be legitimate system prompts or application windows. This allows attackers to deceive users into believing they are interacting with trusted system components while actually engaging with malicious content. The vulnerability operates at the intersection of browser security boundaries and user interface rendering, creating an attack surface where malicious actors can exploit the trust users place in fullscreen applications.
The technical implementation flaw manifests in how Chrome handles fullscreen transition events and window management on Windows operating systems. During fullscreen activation, the browser fails to adequately distinguish between legitimate fullscreen requests from trusted domains and maliciously crafted requests that attempt to mimic system dialogs or application interfaces. This inadequate separation of concerns allows attackers to construct HTML pages that, when triggered, cause Chrome to render interfaces that can masquerade as system prompts, security warnings, or application windows. The vulnerability specifically exploits the window management APIs available on Windows platforms, leveraging the way Chrome interacts with the operating system's fullscreen capabilities to create deceptive user experiences.
The operational impact of this vulnerability extends beyond simple deception to potentially enable more sophisticated attacks such as credential theft, phishing attempts, and privilege escalation. Users who encounter malicious fullscreen pages may be tricked into entering sensitive information, clicking on deceptive links, or performing actions they would not normally undertake when presented with what appears to be a legitimate system interface. The medium severity classification reflects the potential for significant user deception and the ability to bypass traditional security measures that rely on visual verification of system interfaces. This vulnerability particularly affects users who frequently interact with web applications that require fullscreen mode or those who may not be aware of the risks associated with fullscreen browser interfaces. The attack vector requires user interaction through a malicious webpage, making it a client-side exploitation technique that aligns with common phishing and social engineering approaches.
Mitigation strategies should focus on immediate browser updates to versions 132.0.6834.83 and later, which contain the necessary patches to address the fullscreen validation logic. Users should also exercise caution when encountering fullscreen prompts from unfamiliar websites and verify the legitimacy of such requests through multiple verification methods. Security administrators should implement browser hardening policies that restrict fullscreen capabilities for untrusted domains and consider deploying additional security layers such as content security policies that can prevent malicious fullscreen requests. The fix implemented by Google addresses the core validation issue by strengthening the verification process for fullscreen requests and ensuring that the browser properly distinguishes between legitimate and malicious fullscreen transitions. Organizations should also consider implementing user education programs to raise awareness about UI spoofing techniques and the importance of verifying interface authenticity before providing sensitive information. This vulnerability demonstrates the ongoing challenges in browser security where user interface elements can be exploited to bypass traditional security controls, highlighting the importance of maintaining robust validation mechanisms throughout the browser's rendering and interaction pipeline. The implementation aligns with security best practices outlined in CWE-602 and addresses specific ATT&CK techniques related to user interface deception and credential access through social engineering approaches.