CVE-2017-15426 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 identified as CVE-2017-15426 represents a critical security flaw in Google Chrome's Omnibox implementation that enabled remote attackers to conduct domain spoofing attacks using internationalized domain names with homograph characters. This weakness specifically affected Chrome versions prior to 63.0.3239.84 and exploited the browser's insufficient policy enforcement mechanisms when processing internationalized domain names. The vulnerability leveraged the ability of attackers to craft domain names that appear visually identical or nearly identical to legitimate domains through the use of characters from different Unicode scripts that resemble Latin characters but have different code points.
The technical flaw stems from how Chrome's Omnibox handled internationalized domain names, particularly when displaying them in the address bar and navigation interface. Attackers could register domain names containing Unicode characters that visually mimic standard Latin characters, creating deceptive URLs that would appear legitimate to users. For instance, characters from Cyrillic, Arabic, or other Unicode scripts could be used to create domains that look identical to well-known sites like google.com or facebook.com, allowing attackers to exploit user trust and potentially capture credentials or sensitive information. This issue falls under the CWE-1004 category of "Insufficient Policy Enforcement" and specifically relates to CWE-1032 which deals with "Improper Enforcement of Message Integrity" and CWE-1035 which addresses "Improper Enforcement of Message Authenticity."
The operational impact of this vulnerability was significant as it enabled sophisticated phishing attacks that could bypass traditional security measures. Users would see seemingly legitimate URLs in their browser's address bar, making it extremely difficult to distinguish between authentic and malicious sites. This type of attack directly aligns with the tactics described in the MITRE ATT&CK framework under T1566, specifically "Phishing" techniques, where attackers leverage visual deception to manipulate users into trusting malicious websites. The vulnerability essentially undermined the browser's user interface security by allowing attackers to exploit the trust model that users place in the address bar, creating an environment where users might unknowingly navigate to compromised sites.
Mitigation strategies for CVE-2017-15426 primarily focused on updating to Chrome version 63.0.3239.84 or later, which implemented enhanced policy enforcement for internationalized domain names. Security professionals recommended that organizations enforce mandatory browser updates through enterprise management systems to ensure all users had protection against this vulnerability. Additional defensive measures included user education about the risks of visual domain spoofing, implementation of DNS-based security solutions such as DNS over HTTPS or DNS over TLS, and enhanced monitoring of suspicious domain registrations. The vulnerability highlighted the importance of proper Unicode handling in security-critical applications and led to improved internationalized domain name processing standards across web browsers. Organizations should have implemented comprehensive patch management procedures and conducted regular security assessments to identify and remediate similar vulnerabilities in their browser configurations and web applications.