CVE-2008-7293 in Firefox
Summary
by MITRE
Mozilla Firefox before 4 cannot properly restrict modifications to cookies established in HTTPS sessions, which allows man-in-the-middle attackers to overwrite or delete arbitrary cookies via a Set-Cookie header in an HTTP response, related to lack of the HTTP Strict Transport Security (HSTS) includeSubDomains feature, aka a "cookie forcing" issue.
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Analysis
by VulDB Data Team • 11/17/2021
This vulnerability represents a critical security flaw in Mozilla Firefox versions prior to 4.0 that fundamentally undermines the integrity of secure session management. The issue stems from Firefox's inability to properly enforce transport security policies for cookies established during HTTPS sessions, creating a dangerous gap in web application security. When users interact with secure websites, cookies are typically set with security attributes that prevent them from being accessed or modified over unencrypted connections. However, this flaw allows attackers positioned between the user and the web server to exploit the lack of proper HSTS implementation to manipulate cookie values.
The technical root cause of this vulnerability lies in Firefox's incomplete implementation of HTTP Strict Transport Security mechanisms, specifically the missing includeSubDomains directive that should enforce secure connections across all subdomains of a website. This deficiency creates an attack surface where man-in-the-middle adversaries can intercept HTTP responses and inject malicious Set-Cookie headers that override legitimate session cookies. The vulnerability operates under CWE-310, which addresses cryptographic weaknesses in security protocols, and specifically relates to improper certificate validation and transport layer security enforcement. Attackers can leverage this weakness to perform session hijacking attacks where they overwrite user session cookies with their own values, effectively taking control of user accounts.
The operational impact of this vulnerability extends beyond simple cookie manipulation to encompass full session compromise and potential credential theft. When users navigate to websites that rely on secure cookies for authentication, attackers can force the browser to accept insecure cookie modifications that persist across subsequent requests. This creates a persistent threat where users remain logged into compromised sessions without awareness of the attack. The vulnerability also impacts the broader web ecosystem by weakening the security model that browsers provide to protect against session fixation and cookie-based attacks. According to ATT&CK framework category T1566, this represents a credential access technique that exploits transport layer security gaps to manipulate authentication tokens.
Security researchers have documented how this vulnerability enables sophisticated attacks where attackers can maintain persistent access to user accounts by overwriting session cookies with their own session identifiers. The lack of proper HSTS enforcement means that even if users initially connect to a secure site, subsequent connections to the same domain that might be redirected to HTTP can be exploited to overwrite legitimate cookies. This creates a cascading effect where attackers can maintain access across multiple sessions and potentially escalate privileges within web applications. Organizations using Firefox versions before 4.0 were particularly vulnerable because the browser failed to implement the necessary security mechanisms that would have protected against such attacks. The vulnerability demonstrates the critical importance of proper transport security implementation and highlights how even minor implementation gaps can create significant security risks in web browsers.
Mitigation strategies for this vulnerability require immediate browser updates to versions that properly implement HSTS including the includeSubDomains directive. Security administrators should also implement additional network-level protections such as enforcing HTTPS-only policies and monitoring for unusual cookie modification patterns. Organizations must ensure that all web applications properly implement secure cookie attributes including HttpOnly, Secure, and SameSite flags to provide additional layers of protection. The vulnerability underscores the necessity of comprehensive security testing that includes transport layer security validation and proper implementation of security standards such as RFC 6797 for HSTS. Regular security audits and vulnerability assessments should include verification of browser security implementations to prevent exploitation of similar transport security gaps that could compromise user sessions and data integrity.