CVE-2023-49060 in Firefox
Summary
by MITRE • 11/21/2023
An attacker could have accessed internal pages or data by ex-filtrating a security key from ReaderMode via the `referrerpolicy` attribute. This vulnerability affects Firefox for iOS < 120.
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Analysis
by VulDB Data Team • 12/15/2023
This vulnerability represents a critical information disclosure flaw in Firefox for iOS versions prior to 120, where an attacker could potentially access internal pages or sensitive data through a security key exfiltration technique. The flaw specifically leverages the referrerpolicy attribute to manipulate how referral information is transmitted when navigating between pages, creating an avenue for unauthorized data access. The vulnerability stems from inadequate handling of the referrerpolicy attribute within ReaderMode functionality, which is designed to strip away potentially sensitive information from web pages for reading purposes. This particular implementation allows malicious actors to exploit the attribute's behavior to extract security keys or other sensitive data that should remain protected within the browser's internal mechanisms.
The technical implementation of this vulnerability involves the manipulation of HTTP referrer headers through the referrerpolicy attribute, which controls how much referral information is sent when navigating from one page to another. In Firefox for iOS, the ReaderMode component fails to properly sanitize or validate the referrerpolicy attribute when processing internal page navigation, allowing an attacker to craft specific requests that can cause the browser to leak security key information. This type of flaw falls under the CWE-200 category of Information Exposure, where sensitive data is inadvertently revealed to unauthorized parties. The vulnerability specifically impacts the browser's security model by undermining the isolation between different browsing contexts and potentially allowing cross-site information leakage.
The operational impact of this vulnerability extends beyond simple data exposure, as it could enable attackers to gain unauthorized access to internal network resources or sensitive user data that should remain isolated within the browser's secure environment. An attacker could potentially leverage this flaw to access pages that are normally protected by access controls or to extract authentication tokens and other security keys that are critical for maintaining user session integrity. The vulnerability particularly affects mobile users of Firefox for iOS, as the mobile browser implementation may have different security boundaries compared to desktop versions, creating additional attack surface. This issue represents a significant threat to user privacy and security, as it allows for the potential exfiltration of sensitive information through seemingly benign navigation patterns.
Mitigation strategies for this vulnerability primarily involve updating to Firefox for iOS version 120 or later, where the referrerpolicy attribute handling has been properly addressed. Organizations should implement immediate patch management procedures to ensure all affected devices are updated promptly. Additionally, network administrators should monitor for suspicious navigation patterns or referrer header anomalies that might indicate exploitation attempts. The fix typically involves strengthening the validation of referrerpolicy attributes within ReaderMode functionality and ensuring that security keys or sensitive data are properly isolated from external navigation requests. Security teams should also consider implementing network-based detection measures that can identify unusual referrer header behaviors that might indicate exploitation attempts. This vulnerability highlights the importance of proper attribute validation in web browser implementations and demonstrates how seemingly simple features can create significant security risks when not properly secured. The remediation approach aligns with ATT&CK technique T1566.002 for credential access through social engineering and T1071.004 for application layer protocol usage, as it involves manipulation of browser protocols and information extraction techniques.