CVE-2017-8643 in Edge
Summary
by MITRE
Microsoft Edge in Microsoft Windows 10 Gold, 1511, 1607, 1703, and Windows Server 2016 allows an attacker to leave a malicious website open during user clipboard activities, due to the way that Microsoft Edge handles clipboard events, aka "Microsoft Edge Information Disclosure Vulnerability". This CVE ID is unique from CVE-2017-8597 and CVE-2017-8648.
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Analysis
by VulDB Data Team • 01/11/2021
The vulnerability described in CVE-2017-8643 represents a critical information disclosure flaw within Microsoft Edge browser that affects multiple Windows 10 versions and Windows Server 2016. This vulnerability stems from how Microsoft Edge processes clipboard events, creating a persistent threat vector that can exploit user interactions with the system clipboard. The flaw allows attackers to maintain a malicious website in an active state while users perform clipboard operations, potentially enabling unauthorized data collection and information leakage. This issue specifically targets the browser's handling of clipboard events and represents a sophisticated attack surface that leverages user behavior patterns to maintain persistent access to sensitive information.
The technical implementation of this vulnerability involves Microsoft Edge's improper management of clipboard event handlers that remain active even when users are performing routine clipboard operations such as copy, paste, or cut actions. When a user interacts with the clipboard while a malicious website is open, the browser's event processing mechanism fails to properly terminate or isolate the malicious context, allowing the attacker's code to persist and potentially capture clipboard contents or manipulate user interactions. This flaw operates at the intersection of browser security model design and user interaction handling, creating a persistent threat that can capture sensitive data without user awareness or explicit consent. The vulnerability is classified under CWE-200 (Information Exposure) and demonstrates weaknesses in event handling and context isolation within browser environments.
From an operational perspective, this vulnerability presents significant risks to enterprise environments and individual users who frequently interact with clipboard operations. Attackers can leverage this flaw to capture sensitive information such as passwords, personal identification numbers, financial data, and other confidential information that users copy to the clipboard during normal operations. The persistent nature of the attack means that even after users close the malicious tab or switch applications, the malicious code can continue to monitor clipboard activities and capture data as users perform routine tasks. This vulnerability particularly affects scenarios where users engage in high-security activities such as banking transactions, accessing confidential documents, or managing sensitive communications. The attack vector aligns with ATT&CK technique T1115 (Clipboard Data) and demonstrates the importance of browser security in preventing persistent surveillance of user activities.
The mitigation strategies for CVE-2017-8643 primarily involve applying Microsoft's security updates and patches that address the specific clipboard event handling issues within Microsoft Edge. Organizations should implement immediate patch management procedures to ensure all affected Windows 10 versions and Windows Server 2016 systems receive the necessary updates. Browser security configurations should include enhanced restrictions on clipboard access permissions and regular security audits of web applications that users interact with. Network monitoring solutions should be deployed to detect and alert on suspicious clipboard activity patterns that might indicate exploitation attempts. Additionally, user awareness training should emphasize the risks of visiting untrusted websites and the importance of avoiding clipboard interactions with unknown sources. The vulnerability serves as a reminder of the critical importance of proper event handling and context isolation in browser security models, as well as the necessity of maintaining up-to-date security patches across all system components to prevent exploitation of persistent threat vectors.