CVE-2018-18348 in Chrome
Summary
by MITRE
Incorrect handling of bidirectional domain names with RTL characters in Omnibox in Google Chrome prior to 71.0.3578.80 allowed a remote attacker to spoof the contents of the Omnibox (URL bar) 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 • 06/18/2023
This vulnerability resides in the core user interface component of Google Chrome known as the Omnibox, which displays and processes URL addresses. The flaw specifically manifests when processing domain names that contain right-to-left text characters, creating a sophisticated spoofing attack vector. The vulnerability stems from improper bidirectional text handling within the browser's address bar rendering system, where the presence of right-to-left Unicode characters can cause the browser to display domain names in a manner that obscures the actual origin of web content. This creates a deceptive user experience where malicious actors can craft domain names that appear legitimate while actually directing users to harmful destinations.
The technical implementation of this vulnerability involves the manipulation of Unicode bidirectional control characters within domain name labels. When Chrome processes such domain names, the bidirectional algorithm fails to properly handle the mixing of left-to-right and right-to-left text segments, causing the visual representation of the URL to differ from its actual parsed structure. This allows attackers to construct domain names where the right-to-left characters can alter how the URL appears to users while maintaining the functional integrity of the domain. The vulnerability affects versions prior to 71.0.3578.80 and represents a critical flaw in the browser's user interface security model, as it directly impacts user trust and decision-making during web navigation.
The operational impact of this vulnerability extends beyond simple visual deception, as it enables sophisticated phishing attacks and man-in-the-middle scenarios. Attackers can craft domain names that appear to display legitimate URLs while actually redirecting users to malicious sites, potentially bypassing traditional security mechanisms. Users may be deceived into trusting fraudulent websites that appear to be legitimate financial institutions, social media platforms, or other trusted services. This vulnerability operates at the intersection of text rendering, security user interface design, and social engineering, creating a particularly dangerous attack vector that can be difficult to detect even by security-conscious users. The attack requires no special privileges or complex exploitation techniques, making it accessible to adversaries with minimal technical expertise.
Mitigation strategies for this vulnerability involve implementing proper bidirectional text handling in web browsers and ensuring that URL display logic correctly accounts for Unicode text directionality. Browser vendors should adopt defensive programming practices that sanitize and normalize text before display, particularly in security-critical user interface elements. Users should maintain updated browser versions and exercise caution when navigating to unfamiliar websites. Security organizations should monitor for patterns of malicious domain registration that exploit similar text manipulation techniques. This vulnerability aligns with CWE-174, which addresses improper handling of bidirectional text, and relates to ATT&CK technique T1566, which covers social engineering through deceptive web content. The fix implemented by Google in Chrome 71.0.3578.80 involved enhanced Unicode text processing and stricter validation of domain name display logic to prevent such visual spoofing attacks.