CVE-2011-4684 in Web Browser
Summary
by MITRE
Opera before 11.60 does not properly handle certificate revocation, which has unspecified impact and remote attack vectors related to "corner cases."
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Analysis
by VulDB Data Team • 03/23/2025
The vulnerability identified as CVE-2011-4684 affects Opera web browsers version 11.59 and earlier, specifically targeting the browser's handling of certificate revocation mechanisms. This flaw represents a critical security weakness in the browser's implementation of the certificate validation process, where the software fails to properly manage and verify certificate revocation status in certain edge cases. The vulnerability stems from the browser's insufficient processing of certificate revocation lists and online certificate status protocol responses, creating potential security gaps that could be exploited by malicious actors.
The technical implementation of this vulnerability lies in Opera's certificate validation subsystem which does not adequately account for various corner cases during the certificate revocation checking process. When browsers validate SSL/TLS certificates, they must verify not only the certificate's authenticity but also its current validity status, including whether it has been revoked by the issuing certificate authority. Opera's failure to properly handle these revocation checks in specific scenarios means that compromised certificates could potentially be accepted as valid, undermining the entire public key infrastructure that secures web communications. This issue falls under the broader category of certificate validation flaws that are categorized as CWE-295 in the Common Weakness Enumeration system, specifically relating to improper certificate validation.
The operational impact of this vulnerability extends beyond simple certificate acceptance issues, as it creates opportunities for man-in-the-middle attacks and certificate substitution attacks. Attackers could potentially exploit this weakness to present revoked certificates that Opera would incorrectly accept as valid, allowing them to intercept and decrypt communications between users and web servers. The remote attack vectors associated with this vulnerability mean that malicious actors could exploit it without requiring physical access to the target system, making it particularly dangerous in the context of web-based attacks. This vulnerability aligns with several tactics described in the MITRE ATT&CK framework under the T1552 category, specifically related to credentials harvesting and the exploitation of trust relationships.
The implications of this vulnerability are significant for organizations relying on Opera browsers for secure web communications, as it fundamentally undermines the trust model that SSL/TLS certificates are designed to establish. The unspecified impact mentioned in the CVE description suggests that the consequences could vary depending on the specific corner case encountered, potentially ranging from information disclosure to complete session hijacking. Organizations using affected versions of Opera should prioritize immediate remediation through browser updates, as the vulnerability represents a fundamental breakdown in the security architecture that could be exploited to compromise user sessions, steal sensitive data, and undermine the integrity of secure web communications. The vulnerability demonstrates the critical importance of proper certificate validation implementation and highlights the need for comprehensive testing of edge cases in security-critical components of web browsers.