CVE-2015-4508 in Firefox
Summary
by MITRE
Mozilla Firefox before 41.0, when reader mode is enabled, allows remote attackers to spoof the relationship between address-bar URLs and web content via a crafted web site.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 06/19/2022
The vulnerability identified as CVE-2015-4508 represents a significant security flaw in Mozilla Firefox versions prior to 41.0 that affects the browser's reader mode functionality. This issue stems from the improper handling of URL relationships within the reader mode context, creating a potential vector for sophisticated phishing attacks and content spoofing. The vulnerability specifically impacts how Firefox displays website addresses in the address bar when reader mode is active, allowing malicious actors to manipulate the perceived origin of web content.
The technical implementation of this flaw occurs within Firefox's reader mode component where the browser fails to properly validate or display the actual URL associated with content being rendered in reader view. When users navigate to a website with reader mode enabled, the browser should maintain a clear distinction between the original site's address and the reader mode interface. However, the vulnerability allows attackers to craft malicious websites that can display misleading address bar information, making it appear as though the content originates from a trusted domain while actually serving content from a different source.
This vulnerability directly relates to CWE-601 and CWE-79, representing URL redirection issues and cross-site scripting vulnerabilities respectively. The operational impact of CVE-2015-4508 extends beyond simple visual deception as it enables attackers to create highly convincing phishing scenarios. Users may be tricked into believing they are visiting legitimate websites while actually interacting with malicious content, potentially leading to credential theft, financial fraud, or data exfiltration. The attack vector is particularly dangerous because it leverages the browser's legitimate reader mode feature to obscure the true source of content, making traditional security warnings less effective.
The security implications of this vulnerability align with several tactics described in the MITRE ATT&CK framework, particularly those related to initial access and credential access. Attackers can exploit this flaw by creating malicious websites that appear to be legitimate services, using the reader mode functionality to hide the true origin of the content. The vulnerability affects user trust in the browser's address bar, which is a fundamental security mechanism designed to verify website authenticity. Organizations and individuals using affected Firefox versions face increased risk of social engineering attacks that leverage this spoofing capability.
Mitigation strategies for CVE-2015-4508 primarily involve upgrading to Firefox version 41.0 or later where the vulnerability has been addressed through improved URL validation and reader mode implementation. System administrators should implement comprehensive browser update policies to ensure all users maintain current versions that include security patches. Additionally, users should be educated about the importance of verifying website addresses even when using reader mode, as the vulnerability specifically exploits the trust placed in this browser feature. Security teams should monitor for indicators of compromise related to malicious websites that may have exploited this vulnerability during its active period, particularly focusing on unusual URL patterns or content delivery that might indicate spoofing attempts.