CVE-2017-15424 in Chrome
Summary
by MITRE
Insufficient policy enforcement in Omnibox in Google Chrome prior to 63.0.3239.84 allowed a remote attacker to perform domain spoofing via IDN homographs in a crafted domain name.
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Analysis
by VulDB Data Team • 05/06/2023
The vulnerability CVE-2017-15424 represents a critical security flaw in Google Chrome's Omnibox implementation that enabled remote attackers to conduct domain spoofing attacks using internationalized domain names. This issue affected Chrome versions prior to 63.0.3239.84 and exploited the browser's insufficient policy enforcement mechanisms when handling internationalized domain name homographs. The vulnerability specifically targeted the way Chrome processed and displayed domain names containing characters from different scripts that appear visually similar but have different Unicode representations, creating opportunities for malicious actors to deceive users into visiting fraudulent websites.
The technical flaw stems from Chrome's inadequate handling of internationalized domain names where attackers could register domains using characters from different Unicode scripts that visually resemble Latin characters. This creates a scenario where a domain name might appear to be a legitimate website like "google.com" but actually contains characters from other scripts such as Cyrillic or Arabic that look nearly identical to the Latin characters. When users visited such crafted domains, the browser would display the deceptive domain name in the address bar, making it extremely difficult for users to distinguish between legitimate and malicious sites. The vulnerability was classified under CWE-645 as insufficient policy enforcement and specifically relates to improper handling of internationalized domain names in the browser's user interface components.
The operational impact of this vulnerability extends beyond simple phishing attacks as it undermines fundamental trust mechanisms in web browsing. Attackers could craft domain names that would appear legitimate to users who might not notice subtle visual differences between characters from different scripts. This creates a significant risk for users who rely on visual cues in the address bar to verify website authenticity, potentially leading to credential theft, financial fraud, and data breaches. The vulnerability particularly affected users who might not be familiar with Unicode character sets or who might not carefully inspect domain names when navigating to websites. This type of attack falls under the ATT&CK technique T1566.001 for credential harvesting through phishing and represents a sophisticated approach to bypassing browser security mechanisms.
Mitigation strategies for this vulnerability required updating to Chrome version 63.0.3239.84 or later where Google implemented enhanced policy enforcement for internationalized domain names. The fix involved improving the browser's handling of Unicode characters in domain names by implementing stricter validation rules and visual indicators that would alert users to potentially deceptive domain names. Organizations should ensure all Chrome installations are kept up to date with the latest security patches and implement additional security measures such as browser security extensions that provide enhanced domain validation. Users should be educated about the risks of internationalized domain name spoofing and trained to carefully inspect URLs even when they appear to be legitimate sites. The vulnerability also highlighted the importance of implementing proper input validation and policy enforcement mechanisms in web browsers and other applications that handle user-facing domain information, aligning with security best practices outlined in various cybersecurity frameworks including NIST SP 800-53 and ISO/IEC 27001 standards for secure application development.