CVE-2008-7270 in OpenSSL
Summary
by MITRE
OpenSSL before 0.9.8j, when SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG is enabled, does not prevent modification of the ciphersuite in the session cache, which allows remote attackers to force the use of a disabled cipher via vectors involving sniffing network traffic to discover a session identifier, a different vulnerability than CVE-2010-4180.
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Analysis
by VulDB Data Team • 10/06/2021
The vulnerability described in CVE-2008-7270 represents a critical flaw in OpenSSL's session management and cipher suite handling mechanisms. This vulnerability exists in OpenSSL versions prior to 0.9.8j and specifically relates to the SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG option which was designed to maintain compatibility with older Netscape clients. The flaw occurs when this particular option is enabled, creating a condition where the SSL session cache can be manipulated by remote attackers to influence cipher suite selection during subsequent connections.
The technical implementation of this vulnerability stems from OpenSSL's improper handling of session resumption when the Netscape compatibility flag is active. When SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG is enabled, the system fails to properly validate or enforce cipher suite restrictions during session cache operations. This creates an opportunity for attackers to observe network traffic and extract session identifiers through packet sniffing techniques. Once obtained, these identifiers can be used to establish new connections where the attacker can force the system to utilize cipher suites that should normally be disabled or restricted.
The operational impact of this vulnerability extends beyond simple cipher suite manipulation, as it fundamentally compromises the security posture of systems relying on OpenSSL for secure communications. Attackers can exploit this weakness to downgrade security protections by forcing the use of weaker cryptographic algorithms, potentially enabling man-in-the-middle attacks or facilitating cryptographic attacks against connections that would otherwise be protected by stronger cipher suites. This vulnerability is particularly concerning because it operates at the protocol level and can be exploited without requiring direct authentication or privileged access to the target system.
The security implications of this vulnerability align with CWE-310, which addresses cryptographic weaknesses in security protocols, and can be mapped to ATT&CK technique T1557.001 for credential access through network sniffing and T1071.001 for application layer protocol usage. The vulnerability demonstrates how legacy compatibility features can introduce security weaknesses that persist even when the original compatibility requirements are no longer relevant. Organizations using affected OpenSSL versions face significant risk of cryptographic downgrade attacks and potential exposure of sensitive communications.
Mitigation strategies for this vulnerability require immediate patching of OpenSSL installations to version 0.9.8j or later, where the improper session cache behavior has been corrected. System administrators should also disable the SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG option if it is not absolutely required for legacy client compatibility. Network monitoring should be enhanced to detect unusual session identifier usage patterns, and security policies should be updated to ensure that cipher suite restrictions are properly enforced even during session resumption operations. Additionally, organizations should conduct comprehensive vulnerability assessments to identify systems that may be using older OpenSSL versions and implement automated patch management processes to prevent similar issues from arising in the future.