CVE-2016-5191 in Chrome
Summary
by MITRE
Bookmark handling in Google Chrome prior to 54.0.2840.59 for Windows, Mac, and Linux; 54.0.2840.85 for Android had insufficient validation of supplied data, which allowed a remote attacker to inject arbitrary scripts or HTML (UXSS) via crafted HTML pages, as demonstrated by an interpretation conflict between userinfo and scheme in an http://javascript:[email protected] URL.
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Analysis
by VulDB Data Team • 10/12/2022
The vulnerability identified as CVE-2016-5191 represents a critical cross-site scripting flaw in Google Chrome's bookmark handling mechanism that affected multiple platform versions prior to specific security releases. This issue stems from inadequate input validation within Chrome's processing of URL schemes and userinfo components, creating a dangerous intersection where user-supplied data could be improperly interpreted during bookmark operations. The vulnerability specifically targets the browser's handling of URLs containing javascript schemes within userinfo sections, where the browser's interpretation of these malformed URLs creates opportunities for malicious code execution through cross-site scripting attacks.
The technical exploitation of this vulnerability occurs through a sophisticated manipulation of URL parsing logic where Chrome's bookmark system fails to properly validate the userinfo component of URLs before processing them. When a malicious URL contains a javascript scheme within the userinfo portion such as http://javascript:[email protected], the browser's inconsistent interpretation between the scheme and userinfo components creates a window for arbitrary script execution. This flaw operates at the intersection of URL parsing and bookmark management, where the browser's attempt to normalize and store such URLs creates a path for malicious payloads to be executed in the context of the user's browsing session. The vulnerability demonstrates a classic case of improper input validation that allows attackers to bypass security mechanisms designed to prevent script execution from untrusted sources.
The operational impact of CVE-2016-5191 extends beyond simple script injection to represent a serious threat to user privacy and system integrity across multiple platforms including Windows, Mac, Linux, and Android environments. Attackers could leverage this vulnerability to execute arbitrary code on victim machines through crafted web pages that manipulate bookmark data, potentially leading to session hijacking, credential theft, or further exploitation of the victim's browser environment. The remote nature of this attack vector means that users could be compromised simply by visiting malicious websites, with the vulnerability affecting all supported platforms simultaneously and creating a significant risk for widespread exploitation. This type of vulnerability falls under the CWE-79 category for Cross-site Scripting, specifically representing a variant that exploits improper validation of user-supplied data within URL handling components.
Mitigation strategies for CVE-2016-5191 require immediate browser updates to the patched versions 54.0.2840.59 for Windows, Mac, and Linux and 54.0.2840.85 for Android, which address the root cause through improved URL parsing and validation mechanisms. Organizations should implement comprehensive patch management protocols to ensure all affected systems receive updates promptly, as the vulnerability represents a persistent threat that could be exploited for extended periods. Additional protective measures include implementing web application firewalls that can detect and block suspicious URL patterns, configuring browser security policies to restrict bookmark manipulation capabilities, and conducting regular security assessments to identify similar validation flaws in other browser components. The vulnerability's classification aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, specifically targeting browser-based execution environments where user interaction with malicious content can lead to complete system compromise through the exploitation of trust relationships within web browsers.