CVE-2018-6048 in Chrome
Summary
by MITRE
Insufficient policy enforcement in Blink in Google Chrome prior to 64.0.3282.119 allowed a remote attacker to potentially leak referrer information via a crafted HTML page.
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Analysis
by VulDB Data Team • 02/03/2023
The vulnerability identified as CVE-2018-6048 represents a critical security flaw in the Blink rendering engine that powers Google Chrome and other Chromium-based browsers. This issue stems from inadequate policy enforcement mechanisms within the browser's core rendering component, specifically affecting the handling of HTTP referrer headers during web page navigation. The vulnerability exists in Chrome versions prior to 64.0.3282.119, creating a window of exposure where malicious actors could exploit the weak security controls to access sensitive referrer information.
The technical nature of this vulnerability lies in the insufficient validation of referrer policies when processing crafted HTML content. When a user visits a malicious webpage containing specially crafted HTML elements, the browser's Blink engine fails to properly enforce the expected referrer policy controls. This allows attackers to craft HTML pages that can potentially extract referrer information from navigation events, even when the browser should have restricted such access. The flaw operates at the intersection of web standards compliance and security policy enforcement, where the rendering engine does not adequately distinguish between legitimate and malicious referrer header handling requests.
The operational impact of this vulnerability extends beyond simple information disclosure, as referrer headers often contain sensitive data about user navigation patterns, source URLs, and potentially confidential information from internal network resources. Attackers could leverage this weakness to perform reconnaissance activities, tracking user behavior across different domains, or to extract sensitive information from internal network resources that might be referenced in referrer headers. The remote exploitation capability means that users could be compromised simply by visiting a malicious webpage, without requiring any additional user interaction or privilege escalation. This vulnerability directly impacts the principle of least privilege and can be classified under CWE-200 as information exposure through improper access control.
The security implications of this flaw align with several ATT&CK techniques including T1071.004 for application layer protocol usage and T1566 for phishing attacks, as malicious actors could use the leaked referrer information to craft more convincing social engineering campaigns. The vulnerability demonstrates a failure in the browser's security model where the expected isolation between different browsing contexts is compromised, allowing cross-domain information leakage. This represents a significant degradation in user privacy and security, particularly in environments where users access sensitive information or conduct confidential activities online.
Mitigation strategies for CVE-2018-6048 primarily focus on updating to Chrome version 64.0.3282.119 or later, which includes the necessary policy enforcement improvements. Organizations should also implement network-level monitoring to detect potential exploitation attempts and ensure comprehensive patch management procedures are in place. Browser security configurations should be reviewed to enforce stricter referrer policies, and users should be educated about the risks of visiting untrusted websites. The vulnerability highlights the importance of proper security policy enforcement in web browsers and demonstrates how seemingly minor implementation gaps can lead to significant privacy and security concerns.