CVE-2020-6403 in Chrome
Summary
by MITRE
Incorrect implementation in Omnibox in Google Chrome on iOS prior to 80.0.3987.87 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 • 05/10/2025
The vulnerability identified as CVE-2020-6403 represents a critical security flaw in Google Chrome's Omnibox implementation on iOS devices. This issue affected versions prior to 80.0.3987.87 and enabled remote attackers to manipulate the visual display of the URL bar, creating a deceptive user experience that could facilitate phishing attacks and other social engineering exploits. The vulnerability specifically targeted the way Chrome handled URL display in its Omnibox component, which serves as the primary interface for users to input and view web addresses.
The technical implementation flaw stemmed from insufficient validation and sanitization of URL components within the Omnibox rendering process. When users navigated to specially crafted HTML pages, the browser would incorrectly process and display manipulated URL information in the address bar, potentially showing misleading domain names or paths that did not correspond to the actual web content being served. This manipulation occurred at the presentation layer rather than the underlying network communication, making it particularly dangerous as users might trust the displayed URL without realizing they were visiting a different site entirely. The vulnerability exploited the difference between how URLs are processed internally versus how they are visually represented to users.
The operational impact of this vulnerability extends beyond simple visual deception to encompass significant security implications for mobile users who rely on Chrome's Omnibox as a primary security indicator. Attackers could craft malicious web pages that display legitimate-looking URLs while actually directing users to phishing sites or sites hosting malware. This flaw particularly affected iOS users who may not have the same level of security awareness as desktop users, and the attack vector was easily accessible through standard web browsing. The vulnerability could be exploited in various contexts including email attachments, social media links, or compromised websites, making it a widespread concern for mobile web security.
This vulnerability aligns with CWE-601 and CWE-79 categories, specifically addressing URL redirection issues and cross-site scripting vulnerabilities where user-controllable input can be manipulated to display deceptive content. From an ATT&CK framework perspective, this flaw maps to T1566 (Phishing) and T1071.004 (Application Layer Protocol: DNS) as it enables attackers to create deceptive web experiences that bypass user security expectations. The issue also relates to T1557 (Adversary-in-the-Middle) as it allows attackers to manipulate the user's perception of network communications without necessarily intercepting or modifying actual network traffic. Organizations should prioritize immediate patching of affected iOS Chrome versions and implement additional monitoring for suspicious URL patterns in mobile environments.
Mitigation strategies for CVE-2020-6403 require both immediate remediation and long-term security enhancements. The primary solution involves updating all affected iOS devices to Chrome version 80.0.3987.87 or later, which contains the necessary code fixes to properly validate URL display in the Omnibox. Security teams should also implement browser security policies that enforce regular updates and monitor for unauthorized browser modifications. Additional defensive measures include user education about URL verification practices, implementing browser security extensions that provide enhanced URL warnings, and establishing monitoring protocols to detect suspicious web content that might exploit similar vulnerabilities. Organizations should also consider deploying network-level security controls that can detect and block known malicious URL patterns, particularly those targeting mobile browsers where such vulnerabilities are more prevalent.