CVE-2019-13761 in Chrome
Summary
by MITRE
Incorrect security UI in Omnibox in Google Chrome prior to 79.0.3945.79 allowed a remote attacker to perform domain spoofing via IDN homographs via a crafted domain name.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 03/10/2024
The vulnerability identified as CVE-2019-13761 represents a critical security flaw in Google Chrome's omnibox user interface that existed prior to version 79.0.3945.79. This issue falls under the broader category of user interface security weaknesses that can be exploited to deceive users into believing they are visiting legitimate websites while actually being directed to malicious counterparts. The vulnerability specifically targets the handling of internationalized domain names and their visual representation within the browser's address bar, creating an environment where attackers can manipulate the display of domain names to appear legitimate while being fundamentally different.
The technical flaw stems from Chrome's implementation of internationalized domain name (IDN) handling within the omnibox interface. When users enter or navigate to internationalized domain names, the browser must convert these names from their Unicode representation to ASCII-compatible encoding known as punycode. However, the vulnerability occurred because Chrome failed to properly display the punycode representation alongside the Unicode representation, allowing attackers to craft domain names that visually appear identical or nearly identical to legitimate domains while using different underlying character sets. This creates a scenario where the browser displays a domain name that looks authentic to users but actually resolves to a different server controlled by the attacker.
The operational impact of this vulnerability is significant as it enables domain spoofing attacks that can bypass user security awareness and traditional phishing detection mechanisms. Attackers can exploit this weakness by registering domain names that contain Unicode characters that visually resemble the characters of legitimate domains, creating deceptive URLs that appear authentic to unsuspecting users. This type of attack is particularly dangerous because users often rely on visual cues in the address bar to verify website legitimacy, and the vulnerability undermines this fundamental security mechanism. The attack vector requires no special privileges or complex exploitation techniques, making it accessible to threat actors with basic knowledge of Unicode character sets and domain registration.
This vulnerability aligns with CWE-640 Weak Password Recovery Mechanism and CWE-74 Improper Neutralization of Special Elements in Output, as it involves improper handling of user interface elements that can be manipulated to create misleading representations. The attack pattern corresponds to techniques described in the MITRE ATT&CK framework under T1566 Phishing and T1071.1001 Application Layer Protocol DNS, where attackers leverage visual deception to manipulate user interactions with web applications. The vulnerability demonstrates how seemingly minor UI implementation details can create significant security risks when they fail to properly account for international character sets and their visual representations.
The recommended mitigations include updating to Chrome version 79.0.3945.79 or later, which implements proper IDN display handling and ensures that Unicode domain names are clearly distinguished from their punycode equivalents. Organizations should also implement additional security measures such as DNS-based security solutions, web application firewalls, and user education programs that emphasize the importance of verifying domain names beyond visual appearance. Browser vendors should continue to improve their IDN handling mechanisms to ensure that internationalized domain names are displayed in a manner that prevents confusion between legitimate and malicious domains. Security teams should monitor for indicators of compromise related to domain spoofing attacks and maintain awareness of the evolving threat landscape surrounding internationalized domain name vulnerabilities.