CVE-2017-15427 in Chrome
Summary
by MITRE
Insufficient policy enforcement in Omnibox in Google Chrome prior to 63.0.3239.84 allowed a socially engineered user to XSS themselves by dragging and dropping a javascript: URL into the URL bar.
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Analysis
by VulDB Data Team • 05/06/2023
The vulnerability identified as CVE-2017-15427 represents a significant security flaw in Google Chrome's Omnibox component that existed prior to version 63.0.3239.84. This issue stems from inadequate policy enforcement mechanisms within the browser's address bar functionality, creating a pathway for malicious actors to exploit user trust through social engineering techniques. The vulnerability specifically targets the drag-and-drop functionality of the Omnibox, which is designed to handle various URL formats including javascript: URLs that execute code directly within the browser context. The flaw demonstrates a critical oversight in Chrome's security model where legitimate user interactions with the browser interface are not properly validated against potential security threats.
The technical exploitation of this vulnerability relies on the ability of a malicious actor to convince a user to perform a seemingly benign action while simultaneously executing malicious code. When a user drags and drops a javascript: URL into the Chrome Omnibox, the browser fails to properly sanitize or validate the content before executing it. This creates a self-XSS (Cross-Site Scripting) scenario where the user becomes the unwitting victim of their own action. The javascript: URL scheme is a legitimate browser feature that allows execution of JavaScript code directly from the address bar, but when combined with drag-and-drop functionality without proper input validation, it becomes a vector for code execution. The vulnerability essentially bypasses Chrome's normal security restrictions that would typically prevent arbitrary code execution from user-controlled inputs.
The operational impact of this vulnerability extends beyond simple code execution, as it can be leveraged to perform a wide range of malicious activities including credential theft, session hijacking, and data exfiltration. The social engineering aspect of this attack makes it particularly dangerous because it relies on user behavior rather than technical exploits that might be detected by traditional security measures. Attackers can craft convincing phishing campaigns that encourage users to drag and drop malicious URLs into their browser, exploiting the trust users place in their own browser interface. This vulnerability aligns with CWE-79 (Cross-site Scripting) and CWE-20 (Improper Input Validation) categories, as it involves both the execution of malicious code through user input and insufficient validation of the input itself. The attack vector also corresponds to techniques described in the MITRE ATT&CK framework under T1059.007 (Command and Scripting Interpreter: JavaScript) and T1566 (Phishing) tactics.
Mitigation strategies for this vulnerability require both immediate patching and enhanced user awareness training. The most effective solution involves updating to Chrome version 63.0.3239.84 or later, which implements proper validation of drag-and-drop operations within the Omnibox. Additionally, browser security configurations should include enhanced input sanitization for all URL schemes, particularly those that execute code. Organizations should implement security awareness programs that educate users about the risks of drag-and-drop operations with unknown URLs and the importance of verifying the legitimacy of content before interacting with it. The vulnerability highlights the importance of defense-in-depth strategies where multiple layers of security controls work together to prevent exploitation, including browser security policies, user education, and network monitoring solutions that can detect suspicious drag-and-drop activities within browser environments.