CVE-2020-6501 in Chrome
Summary
by MITRE
Insufficient policy enforcement in CSP in Google Chrome prior to 80.0.3987.87 allowed a remote attacker to bypass content security policy via a crafted HTML page.
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Analysis
by VulDB Data Team • 06/04/2020
The vulnerability identified as CVE-2020-6501 represents a critical weakness in Google Chrome's Content Security Policy implementation that existed prior to version 80.0.3987.87. This flaw falls under the category of insufficient policy enforcement where the browser's security mechanisms failed to properly validate and enforce content security restrictions. The vulnerability specifically affects the browser's handling of crafted HTML pages that could manipulate the Content Security Policy directives, potentially allowing malicious actors to bypass intended security boundaries and execute unauthorized code or access restricted resources.
The technical nature of this vulnerability stems from a gap in Chrome's policy enforcement mechanism where certain HTML elements or attributes could be manipulated to circumvent the security controls that should prevent cross-site scripting attacks and other code injection scenarios. This issue is particularly concerning because Content Security Policy serves as a fundamental defense mechanism against various web-based attacks including XSS, data injection, and malicious script execution. The flaw likely involved improper validation of HTML content or insufficient sanitization of policy directives when processing specially crafted web pages that could contain malicious elements designed to exploit the policy enforcement gap.
From an operational impact perspective, this vulnerability created a significant risk for Chrome users as remote attackers could leverage this weakness to bypass security protections that are critical for preventing malicious code execution. The ability to craft HTML pages that could bypass CSP means that attackers could potentially deliver malicious payloads that would otherwise be blocked by standard security controls. This vulnerability could enable attackers to perform actions such as injecting malicious scripts into web pages, accessing sensitive user data, or redirecting users to malicious sites without triggering the expected security warnings or protections that CSP is designed to provide.
The vulnerability demonstrates a clear violation of security principles that aligns with CWE-693, which addresses inadequate protection mechanisms where security controls fail to properly protect against specific threats. This weakness directly impacts the browser's ability to maintain isolation between different security domains and could potentially allow privilege escalation or information disclosure scenarios. The attack vector is particularly dangerous because it requires only a single crafted HTML page to exploit the vulnerability, making it easily deployable in phishing campaigns, drive-by download scenarios, or other web-based attack vectors.
Organizations and users should have implemented immediate mitigations by updating to Chrome version 80.0.3987.87 or later where this vulnerability was patched. The patch likely addressed the policy enforcement gap by strengthening the validation of HTML content and ensuring that CSP directives are properly enforced regardless of the page structure or content manipulation attempts. Security teams should also consider implementing additional monitoring for suspicious HTML content and maintaining awareness of similar vulnerabilities in other browser components. The incident highlights the importance of continuous security testing and validation of security controls, particularly those that form the core defense mechanisms against web-based attacks. This vulnerability serves as a reminder of the critical importance of proper policy enforcement in security systems and the potential consequences when such mechanisms fail to provide adequate protection against malicious actors attempting to exploit browser security features.