CVE-2021-38009 in Chrome
Summary
by MITRE • 12/23/2021
Inappropriate implementation in cache in Google Chrome prior to 96.0.4664.45 allowed a remote attacker to leak cross-origin data via a crafted HTML page.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 12/26/2021
The vulnerability identified as CVE-2021-38009 represents a critical security flaw in Google Chrome's cache implementation that existed prior to version 96.0.4664.45. This issue falls under the category of cross-origin data leakage, where an attacker can exploit improperly managed caching mechanisms to access sensitive information from different origins. The vulnerability stems from inadequate isolation between cached resources from different web origins, creating a pathway for unauthorized data exposure.
The technical implementation flaw resides in Chrome's handling of cached content where the browser fails to properly enforce cross-origin restrictions when serving cached resources. When a malicious actor crafts a specific HTML page, they can manipulate the browser's cache behavior to retrieve data that should be restricted to a particular origin. This occurs because the cache mechanism does not adequately validate or sanitize cross-origin requests before serving cached content, allowing for information disclosure attacks that violate fundamental web security principles.
From an operational impact perspective, this vulnerability enables remote attackers to perform cross-origin information leakage attacks that could compromise user privacy and data confidentiality. The attack vector requires only a crafted HTML page that leverages the browser's caching behavior to access cached resources from other origins. This could potentially expose sensitive user data, session information, or other confidential content that should remain isolated between different web domains. The vulnerability is particularly concerning because it operates entirely within the browser environment without requiring any special privileges or user interaction beyond visiting a malicious website.
The security implications of this vulnerability align with CWE-200, which addresses improper information exposure, and can be mapped to ATT&CK technique T1566 for social engineering attacks that leverage browser vulnerabilities. Organizations and users should immediately update to Chrome version 96.0.4664.45 or later to remediate this issue. Additional mitigations include implementing strict content security policies, monitoring for unusual cache behavior, and ensuring users maintain current browser versions. Network administrators should also consider deploying web application firewalls that can detect and block suspicious caching-related requests that may indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper cache isolation mechanisms in modern web browsers and highlights the ongoing challenges in maintaining secure cross-origin resource sharing implementations.