CVE-2021-38015 in Chrome
Summary
by MITRE • 12/23/2021
Inappropriate implementation in input in Google Chrome prior to 96.0.4664.45 allowed an attacker who convinced a user to install a malicious extension to bypass navigation restrictions via a crafted Chrome Extension.
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Analysis
by VulDB Data Team • 12/26/2021
The vulnerability identified as CVE-2021-38015 represents a critical security flaw in Google Chrome's extension management system that could enable attackers to circumvent navigation restrictions through malicious extensions. This issue stems from an inappropriate implementation in how Chrome handles input validation for extension installations, particularly when dealing with navigation restrictions that are typically enforced by browser policies and security mechanisms.
The technical flaw manifests in Chrome's extension installation process where the browser fails to properly validate the input parameters associated with extension installation requests. When a user installs a malicious extension, the vulnerability allows the attacker to manipulate the extension's behavior to bypass restrictions that would normally prevent navigation to specific domains or content types. This weakness is particularly dangerous because it leverages the trust model inherent in browser extension systems, where users typically grant extensions elevated permissions based on their perceived legitimacy.
The operational impact of this vulnerability extends beyond simple navigation bypassing, as it represents a potential vector for more sophisticated attacks including phishing, data exfiltration, and privilege escalation. Attackers could craft extensions that appear legitimate to users while silently circumventing security controls that protect against malicious navigation attempts. This vulnerability particularly affects environments where organizations implement strict navigation policies to prevent access to harmful websites or to maintain compliance with security standards. The risk is amplified when considering that Chrome extensions operate with significant privileges and can access user data, cookies, and browsing history.
The vulnerability aligns with CWE-20, which describes improper input validation, and demonstrates how inadequate validation of extension installation parameters can create security gaps in browser implementations. From an ATT&CK perspective, this weakness maps to techniques involving privilege escalation and persistence through browser extensions, potentially enabling adversaries to maintain access while evading detection mechanisms that rely on navigation restriction enforcement. Organizations implementing security controls that depend on Chrome's navigation restrictions would be particularly vulnerable to attacks exploiting this flaw.
Mitigation strategies should include immediate updates to Chrome browser versions to 96.0.4664.45 or later, which contain the necessary patches to address the input validation issues. Security administrators should also implement additional monitoring of extension installations and conduct regular audits of installed extensions to identify potentially malicious activity. Organizations should consider implementing browser extension whitelisting policies and restricting users from installing extensions from untrusted sources. The vulnerability highlights the importance of maintaining current browser versions and implementing layered security approaches that do not rely solely on single points of defense such as navigation restrictions.