CVE-2020-6488 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-2020-6488 represents a significant security flaw in Google Chrome's download handling mechanisms that existed prior to version 83.0.4103.61. This issue stems from inadequate policy enforcement during the download process, creating a pathway for malicious actors to circumvent intended navigation restrictions that are typically enforced by browser security models. The flaw specifically affects how Chrome processes download requests initiated through crafted HTML pages, allowing attackers to manipulate the browser's behavior in ways that were not properly constrained by the security architecture.
The technical implementation of this vulnerability involves the browser's failure to properly validate and enforce security policies when processing download requests triggered by HTML content. When a user encounters a maliciously crafted webpage, the attacker can construct HTML elements that appear to initiate downloads while simultaneously bypassing the normal navigation restrictions that would typically prevent such actions. This weakness operates at the intersection of browser policy enforcement and HTML processing, where the download initiation mechanism fails to properly verify that the requested action aligns with the current browsing context and security boundaries. The flaw essentially allows an attacker to escalate privileges through download operations that should have been restricted based on the current page's security context and user permissions.
From an operational impact perspective, this vulnerability enables remote attackers to execute potentially harmful actions without proper authorization. An attacker could craft malicious pages that, when visited by a user, would trigger downloads of malicious files while simultaneously bypassing the normal navigation restrictions that would normally prevent such operations. This creates a scenario where users might inadvertently download malware or other harmful content while believing they are simply browsing a legitimate website. The vulnerability is particularly concerning because it operates at the application level within the browser itself, meaning that successful exploitation could lead to complete system compromise depending on the downloaded content and the user's privileges.
The security implications of CVE-2020-6488 align with several common attack patterns documented in the attack framework, particularly those involving browser-based exploitation and privilege escalation. This vulnerability could be leveraged as part of a broader attack chain where an initial compromise is achieved through social engineering or other means, followed by the exploitation of this download bypass mechanism to deliver additional payloads. The flaw demonstrates a failure in Chrome's security model that should have prevented such cross-context operations, representing a breakdown in the principle of least privilege that is fundamental to secure browser design. Security researchers have classified this issue as a policy enforcement failure, which is consistent with common software security vulnerabilities that occur when access control mechanisms fail to properly validate user actions.
Mitigation strategies for this vulnerability center around updating to Chrome version 83.0.4103.61 or later, which includes the necessary patches to properly enforce download policies and prevent the bypass of navigation restrictions. Organizations should implement comprehensive browser update policies to ensure all systems are running patched versions, as this vulnerability could be exploited in targeted attacks against specific user groups. Additionally, administrators should consider implementing additional security controls such as content filtering, web application firewalls, and user education programs to reduce the risk of successful exploitation. The fix implemented by Google addresses the core policy enforcement issue by strengthening the validation mechanisms that govern download operations and ensuring that navigation restrictions are properly enforced regardless of how download requests are initiated. This type of vulnerability highlights the importance of continuous security testing and validation of browser security models, particularly in areas where user interaction and system-level operations intersect.