CVE-2021-38020 in Chrome
Summary
by MITRE • 12/23/2021
Insufficient policy enforcement in contacts picker in Google Chrome on Android prior to 96.0.4664.45 allowed a remote attacker to spoof the contents of the Omnibox (URL bar) via a crafted HTML page.
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Analysis
by VulDB Data Team • 12/26/2021
This vulnerability resides in the contacts picker functionality of Google Chrome for Android, specifically affecting versions prior to 96.0.4664.45. The flaw represents a critical security issue that undermines the browser's ability to properly enforce security policies when interacting with contact data. The vulnerability stems from insufficient validation mechanisms that fail to properly verify the authenticity and integrity of contact information presented to users through the Omnibox interface. This represents a classic case of inadequate input sanitization and policy enforcement that allows malicious actors to manipulate user interfaces in ways that could deceive users about the actual destination or nature of their browsing activity.
The technical exploitation of this vulnerability occurs through a crafted HTML page that manipulates the contacts picker API to display misleading information within the Omnibox. Attackers can leverage this weakness to present false URLs or domain information that appears legitimate to users, potentially enabling phishing attacks or social engineering campaigns. The flaw specifically affects how Chrome handles contact data when displaying information in the address bar, creating a spoofing opportunity that bypasses normal security boundaries. This issue falls under the CWE-693 category of Protection Mechanism Failure, where security controls are insufficient to prevent unauthorized access or manipulation of user interfaces.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a potential vector for user deception and credential theft. Users may be tricked into believing they are visiting legitimate websites when they are actually interacting with malicious content, particularly when the spoofed Omnibox content mimics trusted domains. This vulnerability directly impacts the browser's security model and user trust, as it undermines the fundamental assumption that the Omnibox provides accurate information about the current browsing context. The attack surface is particularly concerning given that mobile browsers are increasingly targeted due to their widespread use and the typically less secure mobile device environments.
Mitigation strategies should focus on immediate browser updates to version 96.0.4664.45 or later, which contain the necessary policy enforcement fixes. Organizations should also implement additional monitoring for suspicious contact picker API usage patterns and consider network-level protections that can detect and block malicious HTML content. The remediation addresses the underlying policy enforcement gap by strengthening input validation and ensuring that contact data cannot be used to manipulate the Omnibox display without proper authorization. This vulnerability demonstrates the importance of maintaining robust security controls in user interface components and highlights the need for comprehensive policy enforcement across all browser APIs, particularly those that interact with user data and system presentation elements. The ATT&CK framework categorizes this under T1059 Command and Scripting Interpreter and T1566 Phishing, as it enables attackers to create deceptive user experiences that can lead to credential compromise and other malicious activities.