CVE-2011-3953 in Chrome
Summary
by MITRE
Google Chrome before 17.0.963.46 does not prevent monitoring of the clipboard after a paste event, which has unspecified impact and remote attack vectors.
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Analysis
by VulDB Data Team • 03/20/2021
The vulnerability identified as CVE-2011-3953 represents a critical security flaw in Google Chrome browsers prior to version 17.0.963.46 that fundamentally undermines user privacy and system security through improper clipboard handling mechanisms. This issue stems from the browser's failure to properly enforce clipboard access restrictions following paste operations, creating a persistent security risk that can be exploited by malicious actors to monitor user data. The vulnerability operates at the intersection of browser security architecture and user interaction patterns, specifically targeting the clipboard monitoring capabilities that should be automatically disabled after paste events occur. The flaw allows for continuous monitoring of clipboard contents even after users have pasted data, potentially exposing sensitive information that was intended to be temporary or ephemeral.
The technical implementation of this vulnerability involves the browser's clipboard API handling and event management system where paste operations should trigger automatic clearing or disabling of clipboard monitoring mechanisms. However, Chrome versions before 17.0.963.46 failed to properly execute this cleanup process, leaving clipboard access permissions active. This behavior creates a persistent threat vector where malicious web pages can continue to monitor clipboard contents even after legitimate paste operations have occurred, effectively bypassing the expected security boundaries that separate normal browser functionality from potentially harmful monitoring activities. The flaw manifests in the browser's event handling architecture where the paste event completion does not properly trigger the necessary clipboard access revocation protocols.
From an operational impact perspective, this vulnerability enables sophisticated attack scenarios that can compromise user data confidentiality and system integrity across multiple threat vectors. The unspecified impact mentioned in the CVE description suggests that attackers could potentially extract sensitive information such as passwords, personal identification numbers, or confidential documents that users have copied to their clipboard. The remote attack vectors indicate that this vulnerability can be exploited through web-based attacks without requiring local system compromise, making it particularly dangerous in enterprise environments where users frequently interact with untrusted web content. This weakness directly violates fundamental security principles related to data isolation and access control, potentially allowing attackers to build comprehensive profiles of user activities and sensitive information exposure patterns.
Security researchers have classified this vulnerability under CWE-200, which addresses "Information Exposure," and it aligns with ATT&CK technique T1555.001 for "Credentials from Password Stores" and T1555.003 for "Credentials from Web Browsers" as it enables unauthorized access to clipboard contents that often contain sensitive authentication data. The vulnerability's exploitation requires minimal user interaction beyond visiting a malicious website, making it particularly effective for phishing campaigns and credential theft operations. Organizations implementing security controls must recognize that this vulnerability can be leveraged for advanced persistent threats where attackers maintain long-term monitoring capabilities over user clipboard contents. The risk assessment for this vulnerability includes potential data breaches, identity theft, and corporate espionage scenarios where sensitive information remains accessible long after initial user interaction with potentially malicious web content.
Mitigation strategies for CVE-2011-3953 require immediate browser version updates to Chrome 17.0.963.46 or later, which contain the necessary patches to properly implement clipboard access controls. Network administrators should implement browser security policies that enforce automatic updates and monitor for vulnerable browser versions in their environments. Additional protective measures include implementing browser security extensions that provide enhanced clipboard monitoring and access control, deploying web application firewalls that can detect and block suspicious clipboard access patterns, and establishing user awareness programs that educate personnel about the risks of visiting untrusted websites. Organizations should also consider implementing clipboard encryption solutions and regular security audits to detect potential exploitation attempts, while maintaining detailed logging of browser activities that might indicate clipboard monitoring behavior. The vulnerability highlights the importance of proper event handling and access control implementation in browser security architectures, emphasizing the need for comprehensive security testing of user interaction components.