CVE-2020-6487 in Chrome
Summary
by MITRE
Insufficient policy enforcement in downloads in Google Chrome prior to 83.0.4103.61 allowed a remote attacker to bypass navigation restrictions via a crafted HTML page.
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Analysis
by VulDB Data Team • 05/05/2025
The vulnerability identified as CVE-2020-6487 represents a critical security flaw in Google Chrome's download policy enforcement mechanisms that existed prior to version 83.0.4103.61. This issue stems from inadequate validation of download restrictions within the browser's security framework, creating a pathway for malicious actors to circumvent intended navigation and content access controls. The flaw specifically affects the browser's handling of crafted HTML pages that attempt to exploit weaknesses in how Chrome processes download requests and enforces access policies. According to CWE-284, this vulnerability manifests as an improper access control condition where the browser fails to properly validate download requests against established security policies. The vulnerability operates at the intersection of web browser security and content delivery mechanisms, where the browser's download handling system does not adequately verify whether a requested download should be permitted based on the current browsing context and security policies.
The technical implementation of this vulnerability involves the manipulation of HTML page elements to trigger download behaviors that bypass Chrome's built-in navigation restriction controls. Attackers can craft malicious web pages containing specially formatted download links or scripts that exploit the browser's policy enforcement gaps. When a user visits such a page, the browser's download system may incorrectly interpret the request, allowing downloads to proceed even when navigation restrictions should have prevented them. This flaw essentially allows an attacker to extend the scope of their malicious activity beyond what would normally be permitted by the browser's security boundaries. The vulnerability demonstrates a clear breakdown in Chrome's security model where the download subsystem operates with insufficient policy validation compared to other browser components. The issue aligns with ATT&CK technique T1195 which covers content injection attacks, where attackers manipulate browser behavior through crafted web content to achieve unauthorized actions.
The operational impact of CVE-2020-6487 extends beyond simple bypass of navigation restrictions, as it could enable more sophisticated attack vectors including the delivery of malicious payloads, data exfiltration, or further exploitation of the compromised browser environment. An attacker could potentially use this vulnerability to download malware or phishing tools directly to a user's system without triggering the browser's security warnings or restrictions that would normally be in place. The vulnerability affects all users of affected Chrome versions, making it particularly dangerous as it requires no special privileges or user interaction beyond visiting a malicious website. This makes it a prime target for drive-by download attacks where users are unknowingly exposed to threats simply by visiting compromised websites. The vulnerability's impact is amplified by the widespread use of Google Chrome, which serves as the default browser for millions of users globally, creating a significant attack surface for threat actors. Organizations using Chrome-based environments for sensitive operations or those with strict access controls may find their security posture compromised by this flaw. The vulnerability also demonstrates the importance of maintaining up-to-date browser versions as a fundamental security control, since the issue was resolved through the 83.0.4103.61 update that properly enforced download policies. This incident underscores the critical need for continuous security monitoring and timely patch deployment to protect against such policy enforcement failures that could be exploited to undermine browser security models.