CVE-2017-5086 in Chrome
Summary
by MITRE
Insufficient Policy Enforcement in Omnibox in Google Chrome prior to 59.0.3071.86 for Windows and Mac 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-2017-5086 represents a critical insufficient policy enforcement issue within Google Chrome's omnibox component, specifically affecting versions prior to 59.0.3071.86 on Windows and Mac platforms. This flaw stems from inadequate handling of internationalized domain names and their potential for homograph attacks, where attackers can exploit visual similarities between characters from different scripts to deceive users. The omnibox, which serves as the browser's address bar and search interface, becomes a vector for malicious activity when it fails to properly validate and display domain names that appear legitimate but are actually fraudulent.
The technical implementation of this vulnerability involves the browser's failure to adequately distinguish between characters from different Unicode scripts that visually resemble each other. Attackers can craft domain names using characters from different alphabets such as Latin, Cyrillic, or Arabic scripts that appear identical or nearly identical to legitimate domains. For instance, a domain name using Cyrillic characters might visually match a well-known website's domain name, creating a deceptive appearance that bypasses traditional security measures. The vulnerability specifically manifests when Chrome processes these internationalized domain names without proper validation, allowing the browser to display misleading URLs that could fool users into believing they are visiting legitimate websites.
This security weakness enables remote attackers to execute domain spoofing attacks with significant operational impact, particularly in phishing and social engineering scenarios. Users may be tricked into entering sensitive information on fraudulent websites that appear to be legitimate, as the browser's address bar fails to clearly indicate the actual domain being visited. The attack vector relies on the human tendency to focus on visual recognition rather than technical domain validation, making it particularly effective against users who may not notice subtle differences in character sets. The vulnerability essentially undermines the fundamental security principle of user authentication and website verification that browsers should provide to protect users from malicious actors.
The operational implications extend beyond simple phishing attacks to encompass broader trust model compromises within the browser environment. When users cannot reliably distinguish between authentic and fraudulent domains through visual cues alone, the entire security ecosystem of web browsing becomes weakened. This vulnerability affects not only individual user security but also enterprise environments where employees may inadvertently access malicious sites that appear legitimate. The impact is particularly severe given that Chrome's omnibox serves as the primary interface for web navigation and security verification, making it a critical component for maintaining user trust and security awareness. Organizations must consider the broader implications of such vulnerabilities when implementing security policies and user education programs.
Mitigation strategies for CVE-2017-5086 primarily involve immediate patching of affected Chrome versions to the secure release of 59.0.3071.86 or later, which implements proper internationalized domain name handling and validation. Additionally, browser vendors should implement robust policy enforcement mechanisms that properly distinguish between different Unicode character sets and provide clear visual indicators when domains contain non-standard characters. The implementation of strict domain validation protocols and enhanced user interface design that highlights potentially suspicious domain names can significantly reduce the risk of successful attacks. Organizations should also consider implementing additional security layers such as DNS-based security solutions, web application firewalls, and user education programs that specifically address the risks associated with internationalized domain names and homograph attacks.
This vulnerability aligns with CWE-1004 which addresses weaknesses in security policy enforcement and demonstrates characteristics consistent with ATT&CK technique T1566 related to spearphishing through social engineering. The flaw exemplifies the challenges in implementing secure internationalization features within web browsers and highlights the need for comprehensive security testing that considers the full spectrum of Unicode character handling and visual deception techniques. Proper implementation of this vulnerability's remediation requires attention to both the technical aspects of domain name processing and the user experience considerations that ensure security without compromising usability.