CVE-2014-8642 in Firefox
Summary
by MITRE
Mozilla Firefox before 35.0 and SeaMonkey before 2.32 do not consider the id-pkix-ocsp-nocheck extension in deciding whether to trust an OCSP responder, which makes it easier for remote attackers to obtain sensitive information by sniffing the network during a session in which there was an incorrect decision to accept a compromised and revoked certificate.
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Analysis
by VulDB Data Team • 03/02/2022
The vulnerability described in CVE-2014-8642 represents a critical flaw in the certificate validation process of Mozilla Firefox versions prior to 35.0 and SeaMonkey versions prior to 2.32. This issue stems from the improper handling of the id-pkix-ocsp-nocheck extension within the Online Certificate Status Protocol implementation. The id-pkix-ocsp-nocheck extension is defined in rfc6960 and serves as a mechanism to indicate that an OCSP responder should not be checked for validity, essentially bypassing the normal certificate status verification process. When browsers fail to properly consider this extension during certificate validation, they may accept certificates that should have been rejected due to revocation status, creating a significant security gap.
The technical flaw manifests in how the affected browsers process OCSP responses when the id-pkix-ocsp-nocheck extension is present. This extension is typically used in scenarios where certificate authorities want to indicate that an OCSP responder's certificate should not be validated, often in situations where the responder certificate itself has been compromised or revoked. However, the vulnerability allows attackers to exploit network sniffing capabilities to manipulate certificate validation decisions. When an attacker can intercept network traffic during certificate validation, they can potentially force the browser to accept a revoked certificate by manipulating the OCSP response, effectively bypassing the intended security controls that should prevent the use of compromised certificates.
This vulnerability significantly impacts the operational security posture of affected systems by creating opportunities for man-in-the-middle attacks and certificate impersonation. The ability to sniff network traffic and manipulate certificate validation decisions means that attackers can potentially establish trust in compromised certificates without proper verification. This creates a pathway for attackers to conduct phishing attacks, perform certificate forgery, or gain unauthorized access to secure systems that rely on proper certificate validation. The impact extends beyond individual user sessions to potentially compromise entire certificate trust chains and undermine the fundamental security assumptions of public key infrastructure implementations.
The vulnerability aligns with several ATT&CK techniques including T1552.001 (Credentials in Files) and T1046 (Network Service Scanning) as attackers can leverage network interception capabilities to manipulate certificate validation processes. From a CWE perspective, this represents a weakness in certificate validation (CWE-295) combined with improper certificate handling (CWE-310). Organizations should immediately update to Firefox 35.0 or later and SeaMonkey 2.32 or later to address this vulnerability. Additional mitigations include implementing network monitoring to detect unusual certificate validation patterns, deploying certificate pinning strategies where appropriate, and ensuring that network traffic is properly encrypted to prevent interception. Security teams should also conduct thorough testing of certificate validation processes to ensure that the updated browsers properly handle all OCSP extensions, including the id-pkix-ocsp-nocheck extension, thereby maintaining the integrity of their PKI implementations.