CVE-2020-6529 in Chrome
Summary
by MITRE
Inappropriate implementation in WebRTC in Google Chrome prior to 84.0.4147.89 allowed an attacker in a privileged network position to leak cross-origin data via a crafted HTML page.
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Analysis
by VulDB Data Team • 05/05/2025
The vulnerability identified as CVE-2020-6529 represents a critical security flaw in Google Chrome's WebRTC implementation that existed prior to version 84.0.4147.89. This issue stems from an inadequate security model within the browser's WebRTC subsystem that fails to properly enforce cross-origin restrictions. The vulnerability specifically affects the handling of WebRTC data channels and media streams when processing maliciously crafted HTML content, creating a pathway for unauthorized data leakage across different origin boundaries. The flaw manifests when Chrome processes WebRTC connections initiated through compromised web pages, allowing attackers to exploit the browser's insufficient validation mechanisms to access resources that should be restricted by the same-origin policy.
The technical implementation flaw resides in how Chrome's WebRTC component handles connection establishment and data transmission when operating in a privileged network position. Attackers can craft HTML pages that trigger specific WebRTC behaviors which bypass normal security boundaries, enabling them to extract information from different origins without proper authorization. This vulnerability operates at the intersection of several security domains including browser security models, network protocols, and web application security. The issue is particularly concerning because WebRTC is designed for real-time communication between browsers, yet the implementation fails to properly isolate connections from different origins. This weakness allows for potential data exfiltration through WebRTC data channels that should be restricted by the browser's security model. The vulnerability can be exploited by attackers who have network access to intercept traffic between the victim browser and WebRTC servers, making it particularly dangerous in environments where network monitoring is possible.
The operational impact of CVE-2020-6529 extends beyond simple data leakage, as it represents a fundamental breakdown in browser security boundaries that could enable more sophisticated attacks. An attacker with access to a privileged network position can leverage this vulnerability to perform cross-origin information disclosure, potentially accessing sensitive data from different websites that users have visited. This includes but is not limited to session tokens, user credentials, personal information, and other confidential data that should remain isolated between different origins. The vulnerability affects all users of affected Chrome versions and can be exploited through simple web page delivery without requiring any special privileges or user interaction beyond visiting the malicious site. The impact is particularly severe in enterprise environments where users may be accessing multiple web applications that handle sensitive data, as the vulnerability could enable attackers to aggregate information across different applications.
Mitigation strategies for CVE-2020-6529 primarily focus on updating to Chrome version 84.0.4147.89 or later, which contains the necessary security patches to address the WebRTC implementation flaw. Organizations should also implement network monitoring solutions to detect unusual WebRTC traffic patterns that might indicate exploitation attempts. Security teams should consider implementing Content Security Policy headers that restrict WebRTC usage and monitor for suspicious connection attempts. Additionally, browser hardening measures including disabling WebRTC when not required and implementing proper network segmentation can reduce the attack surface. The vulnerability aligns with CWE-284 Access Control Issues and represents a specific instance of improper access control in browser security implementations. From an ATT&CK perspective, this vulnerability maps to T1071.005 Application Layer Protocol: Web Protocols and potentially T1566 Phishing, as exploitation typically requires user interaction with malicious web content. Organizations should also consider implementing WebRTC-specific network controls and monitoring to detect potential exploitation attempts and prevent data leakage through this channel.