CVE-2010-3247 in Chrome
Summary
by MITRE
Google Chrome before 6.0.472.53 does not properly restrict the characters in URLs, which allows remote attackers to spoof the appearance of the URL bar via homographic sequences.
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Analysis
by VulDB Data Team • 09/24/2021
The vulnerability identified as CVE-2010-3247 represents a significant security flaw in Google Chrome browsers prior to version 6.0.472.53 that exploited the browser's inadequate handling of character encoding in uniform resource locators. This weakness allowed malicious actors to manipulate URL display through the strategic use of homographic sequences, where characters from different scripts or character sets appear visually identical or nearly identical to legitimate web addresses. The flaw essentially created a condition where attackers could construct URLs using Unicode characters that visually resemble standard ascii characters, thereby deceiving users into believing they were visiting legitimate websites when in fact they were being directed to malicious destinations.
The technical implementation of this vulnerability stems from Chrome's insufficient validation mechanisms for URL parsing and rendering. When processing URLs containing homographic characters, the browser failed to properly normalize or restrict character sets in ways that would prevent visual spoofing attacks. This issue falls under the broader category of character encoding vulnerabilities and specifically relates to CWE-176, which addresses improper handling of character encoding in web applications. The vulnerability exploited the fact that different Unicode characters could share similar visual appearances, particularly when rendered in the browser's address bar, creating a deceptive user experience that bypassed normal security warnings and visual cues.
The operational impact of CVE-2010-3247 was substantial as it enabled sophisticated phishing attacks that could bypass user trust mechanisms. Attackers could craft URLs that appeared legitimate to users while actually directing them to malicious sites, making it particularly dangerous for users who relied on visual inspection of URLs to verify site authenticity. This vulnerability particularly affected users who might not be familiar with Unicode character variations or who were not actively checking for URL discrepancies. The attack vector required remote execution without user interaction beyond clicking a malicious link, making it highly effective in social engineering campaigns. The vulnerability could be exploited across multiple platforms where Chrome was installed, amplifying its potential impact and reach.
Mitigation strategies for CVE-2010-3247 required immediate browser updates to version 6.0.472.53 or later, which implemented proper URL normalization and character restriction mechanisms. Security researchers recommended that users promptly update their Chrome installations to prevent exploitation of this vulnerability. Organizations should have enforced strict browser update policies and implemented additional security measures such as URL filtering and content security policies. The fix addressed the core issue by implementing proper Unicode normalization and character validation in URL parsing, ensuring that homographic sequences could not be used to create misleading visual representations in the address bar. This vulnerability highlighted the importance of proper input validation and character encoding handling in web browsers, leading to improved security practices in subsequent browser implementations and reinforcing the need for robust security testing of international character handling mechanisms.
This vulnerability demonstrates how seemingly innocuous character encoding issues can create significant security risks when not properly addressed in web browser implementations. The attack pattern aligns with techniques described in the attack tree framework, where visual deception serves as a primary attack vector. The remediation efforts for CVE-2010-3247 contributed to industry-wide improvements in how browsers handle international character sets and Unicode normalization, establishing better security practices for similar vulnerabilities that might arise in the future. The incident underscored the critical importance of comprehensive security testing, particularly for internationalization features, and influenced subsequent security standards and best practices in browser security development.