CVE-2017-5106 in Chrome
Summary
by MITRE
Insufficient Policy Enforcement in Omnibox in Google Chrome prior to 60.0.3112.78 for Mac, Windows, Linux, and Android 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 • 01/05/2023
The vulnerability identified as CVE-2017-5106 represents a critical weakness in Google Chrome's handling of internationalized domain names within the omnibox interface. This flaw existed in Chrome versions prior to 60.0.3112.78 across multiple platforms including Mac, Windows, Linux, and Android operating systems. The issue stems from insufficient policy enforcement mechanisms that fail to properly validate and display internationalized domain names, creating opportunities for malicious actors to exploit user trust in the browser's address bar.
The technical implementation of this vulnerability involves the manipulation of internationalized domain name homographs, where attackers can craft domain names that appear visually identical or nearly identical to legitimate websites through the use of Unicode characters from different scripts. When Chrome displays these domains in the omnibox, it fails to adequately distinguish between legitimate and malicious variants, allowing attackers to create deceptive URLs that could fool users into believing they are visiting trusted websites. This occurs because the browser's rendering engine does not properly implement Unicode bidirectional algorithm checks or visual similarity detection mechanisms that would normally prevent such deceptive presentations.
The operational impact of this vulnerability extends beyond simple phishing attacks, as it enables sophisticated social engineering campaigns that can bypass traditional security measures. Attackers can leverage this flaw to create convincing domain spoofing scenarios where malicious websites appear to be legitimate organizations, financial institutions, or service providers. The vulnerability is particularly dangerous because it operates at the user interface level where trust is implicit, making it difficult for even security-aware users to distinguish between genuine and malicious sites. This weakness directly aligns with CWE-1004 which addresses insufficient policy enforcement and can be categorized under ATT&CK technique T1566 for social engineering through deceptive websites.
The exploitation of this vulnerability requires minimal technical skill from attackers, as it relies on the inherent weaknesses in Chrome's domain name presentation logic rather than complex technical attacks. Users are typically unaware of the underlying Unicode character differences that make the deception possible, making the attack vector particularly effective for mass phishing campaigns. The vulnerability affects all platforms where Chrome operates, amplifying its potential impact across different user groups and environments. Organizations using Chrome as their primary browser are particularly at risk, as this flaw can be exploited in targeted attacks against employees and customers without requiring specialized tools or deep technical knowledge.
Mitigation strategies for this vulnerability primarily involve updating to Chrome version 60.0.3112.78 or later, which implements proper Unicode validation and domain name presentation policies. Security administrators should also consider implementing additional browser security measures such as strict content security policies, enhanced phishing protection, and user education programs that focus on recognizing suspicious website indicators. Organizations should conduct regular security assessments to ensure all Chrome installations are properly updated and monitor for potential exploitation attempts. The fix implemented by Google addresses the core issue by strengthening the validation of internationalized domain names and ensuring proper visual distinction between legitimate and potentially malicious domain presentations.