CVE-2021-30587 in Chrome
Summary
by MITRE • 08/04/2021
Inappropriate implementation in Compositing in Google Chrome prior to 92.0.4515.107 allowed a remote attacker to potentially spoof the contents of the Omnibox (URL bar) via a crafted HTML page.
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Analysis
by VulDB Data Team • 08/07/2021
The vulnerability identified as CVE-2021-30587 represents a critical flaw in Google Chrome's compositing engine that enables remote code execution through deceptive user interface manipulation. This issue affects Chrome versions prior to 92.0.4515.107 and specifically targets the browser's handling of the Omnibox component, which serves as the primary interface for URL input and display. The vulnerability stems from an improper implementation in how Chrome processes and renders composited elements, creating a potential attack vector that could deceive users into believing they are visiting a legitimate website when they are actually interacting with malicious content. The flaw resides in the browser's rendering pipeline where the compositing layer fails to properly validate or sanitize the visual representation of URL bar content, allowing attackers to manipulate the displayed information in ways that bypass normal security checks.
The technical exploitation of this vulnerability leverages the browser's compositor to overlay malicious content over the Omnibox display area, creating a false impression of website authenticity. Attackers can craft HTML pages that utilize specific CSS properties and rendering techniques to manipulate how the browser composites the URL bar elements, effectively spoofing the displayed URL and potentially tricking users into entering sensitive information or executing malicious actions. This implementation flaw falls under the category of UI redressing or clickjacking attacks, where the visual deception is achieved through improper handling of browser rendering components. The vulnerability specifically impacts the browser's ability to maintain integrity of the user interface elements that users trust for security verification, making it particularly dangerous in phishing scenarios where attackers seek to exploit user trust in familiar interface elements.
The operational impact of this vulnerability extends beyond simple information deception to potentially enable more sophisticated attacks including credential theft, malware delivery, and privilege escalation. Users interacting with compromised websites could unknowingly grant access to sensitive data or perform actions based on the false URL information displayed in the Omnibox. The attack surface is particularly concerning given that Chrome's compositing engine handles thousands of rendering operations per second across multiple tabs and windows, making it a prime target for exploitation. This vulnerability directly affects the browser's security model by undermining user confidence in the authenticity of URL displays, which is fundamental to web security protocols and user decision-making processes. The risk is amplified in enterprise environments where users may be less vigilant about URL verification, and where the attack could be used to bypass security controls that rely on visible URL indicators.
Mitigation strategies for CVE-2021-30587 primarily focus on updating to Chrome version 92.0.4515.107 or later, which contains the necessary patches to address the compositing implementation flaw. Organizations should implement comprehensive browser update policies and consider automated deployment mechanisms to ensure all users receive the security fixes promptly. Additional defensive measures include implementing browser security extensions that monitor for suspicious rendering behaviors and deploying network-level controls that can detect and block known malicious patterns. The vulnerability demonstrates the importance of maintaining up-to-date browser security implementations and highlights the need for continuous monitoring of browser rendering engines for potential security gaps. Security teams should also consider implementing user education programs focused on recognizing phishing attempts that exploit browser interface elements, as the attack relies heavily on social engineering aspects that complement the technical exploitation. This vulnerability aligns with ATT&CK technique T1071.004 for application layer protocol: DNS and CWE-200 for exposure of sensitive information, emphasizing the need for layered security approaches that protect against both technical and social engineering components of such attacks.