CVE-2016-1657 in Chrome
Summary
by MITRE
The WebContentsImpl::FocusLocationBarByDefault function in content/browser/web_contents/web_contents_impl.cc in Google Chrome before 50.0.2661.75 mishandles focus for certain about:blank pages, which allows remote attackers to spoof the address bar via a crafted URL.
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Analysis
by VulDB Data Team • 07/25/2022
The vulnerability identified as CVE-2016-1657 resides within the WebContentsImpl::FocusLocationBarByDefault function in Google Chrome's content/browser/web_contents/web_contents_impl.cc file. This flaw affects Chrome versions prior to 50.0.2661.75 and represents a significant security weakness that undermines the browser's address bar integrity. The vulnerability specifically targets certain about:blank pages where the browser's focus handling mechanism fails to properly validate or process the URL context, creating an exploitable condition that enables malicious actors to manipulate the address bar display.
This security flaw operates through a sophisticated manipulation of the browser's focus management system where the FocusLocationBarByDefault function incorrectly processes about:blank pages, allowing attackers to craft specific URLs that can deceive users into believing they are visiting a legitimate website. The technical implementation involves the browser's inability to properly distinguish between legitimate navigation sequences and crafted malicious inputs when handling these specific about:blank page scenarios. The vulnerability creates a spoofing opportunity that can be leveraged to present false address bar information to users, effectively bypassing the browser's security mechanisms designed to prevent such deception.
The operational impact of CVE-2016-1657 extends beyond simple address bar manipulation, representing a serious threat to user trust and security awareness. Attackers can exploit this vulnerability to create convincing phishing scenarios where the address bar displays a legitimate-looking URL while the actual page content is malicious. This type of attack falls under the ATT&CK framework's technique T1056.001 for Input Injection and T1566 for Phishing, as it enables attackers to manipulate user perception through browser interface elements. The vulnerability particularly affects users who rely on address bar verification for website legitimacy assessment, potentially leading to credential theft, malware distribution, or financial fraud.
The root cause of this vulnerability aligns with CWE-601, which addresses URL redirector vulnerabilities where applications fail to properly validate or sanitize URL inputs. The flaw demonstrates poor input validation in the browser's navigation handling system, where the FocusLocationBarByDefault function does not adequately verify the context of about:blank page requests. This weakness creates a pathway for attackers to craft URLs that exploit the browser's focus handling logic, potentially allowing them to bypass security measures that depend on address bar integrity for user verification. The vulnerability's classification as a focus management issue in the browser's core rendering engine indicates a fundamental flaw in how Chrome processes navigation events for specific page types.
Mitigation strategies for CVE-2016-1657 require immediate browser updates to version 50.0.2661.75 or later, which implements proper focus handling for about:blank pages. Organizations should also implement network-level protections such as DNS filtering and web application firewalls to detect and block malicious URL patterns. User education remains crucial, emphasizing the importance of verifying website addresses through multiple means beyond address bar inspection. Security monitoring should focus on detecting anomalous navigation patterns and URL structures that might indicate exploitation attempts. The vulnerability's resolution demonstrates the importance of proper input validation and context awareness in browser security implementations, aligning with industry best practices for preventing similar issues in web application security frameworks.