CVE-2009-3046 in Web Browser
Summary
by MITRE
Opera before 10.00 does not check all intermediate X.509 certificates for revocation, which makes it easier for remote SSL servers to bypass validation of the certificate chain via a revoked certificate.
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Analysis
by VulDB Data Team • 08/20/2021
The vulnerability identified as CVE-2009-3046 affects Opera web browsers prior to version 10.00 and represents a significant weakness in the certificate validation process that undermines the security of SSL/TLS connections. This flaw stems from incomplete implementation of certificate revocation checking mechanisms within the browser's SSL validation logic, creating a pathway for malicious actors to exploit the trust model that should protect users from compromised certificates.
The technical flaw manifests in Opera's handling of X.509 certificate chains where the browser fails to validate all intermediate certificates for revocation status during the SSL handshake process. While the end-entity certificate may be properly validated, the intermediate certificates that establish the trust path between the end certificate and the root certificate authority are not consistently checked against revocation lists. This incomplete validation allows an attacker to present a certificate chain where the root or intermediate certificates have been revoked, yet the browser accepts the connection due to the missing revocation checks on intermediate certificates.
This vulnerability creates a substantial operational impact by weakening the fundamental security guarantees that SSL/TLS protocols are designed to provide. Attackers can exploit this weakness by obtaining a valid certificate from a compromised certificate authority or by using certificates that have been revoked for security reasons, yet still establish secure connections through the browser. The security implications extend beyond simple certificate validation failures, as this weakness can enable man-in-the-middle attacks, certificate substitution scenarios, and undermine the entire certificate trust model that internet security relies upon. According to CWE-295, this represents a failure in proper certificate validation, specifically related to insufficient certificate chain validation that allows compromised certificates to be accepted.
The operational impact of this vulnerability is particularly concerning given that Opera was widely used as a web browser during this period, making a large user base susceptible to attacks that could compromise their secure communications. The flaw essentially creates a false sense of security where users believe their connections are properly validated when in fact the certificate chain validation is incomplete. This vulnerability aligns with ATT&CK technique T1552.001, which covers "Unsecured Credentials" and specifically addresses the compromise of certificate validation mechanisms that should protect against malicious certificate usage.
Mitigation strategies for this vulnerability primarily involve upgrading to Opera version 10.00 or later, which includes proper implementation of intermediate certificate revocation checking. Organizations should also implement additional security measures such as monitoring for certificate anomalies, implementing certificate pinning where appropriate, and ensuring that all systems maintain up-to-date certificate validation mechanisms. Network administrators should consider deploying additional security controls that can detect and prevent connections to servers using compromised certificate chains, as the browser alone cannot fully protect against this class of attack. The remediation process should also include comprehensive testing to ensure that certificate validation works correctly across all supported platforms and configurations.