CVE-2015-3278 in nss_compat_ossl
Summary
by MITRE
The cipherstring parsing code in nss_compat_ossl while in multi-keyword mode does not match the expected set of ciphers for a given cipher combination, which allows attackers to have unspecified impact via unknown vectors.
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Analysis
by VulDB Data Team • 11/01/2019
The vulnerability identified as CVE-2015-3278 resides within the nss_compat_ossl library component, specifically affecting the cipherstring parsing functionality when operating in multi-keyword mode. This flaw represents a critical security weakness in the cryptographic configuration handling mechanisms that govern how SSL/TLS cipher suites are processed and validated. The issue manifests when the library fails to properly validate or interpret cipherstring specifications, creating potential pathways for malicious actors to exploit the inconsistent cipher selection behavior. The vulnerability falls under the category of cryptographic weakness and configuration error, with implications for secure communication protocols that depend on proper cipher suite handling.
The technical implementation flaw stems from the parsing logic within the nss_compat_ossl library where the cipherstring processing code does not accurately validate the expected cipher combinations against the actual cipherstring input. This parsing discrepancy occurs specifically during multi-keyword mode operations, where multiple cipher specifications are processed simultaneously. The failure to match expected cipher sets creates a scenario where attackers can potentially manipulate cipherstring inputs to bypass intended security controls or inject unintended cipher configurations. The vulnerability is classified under CWE-295 which deals with improper certificate validation and CWE-310 which addresses cryptographic issues, both of which are directly applicable to the cipherstring validation failure. The operational impact of this vulnerability extends beyond simple configuration errors as it can enable man-in-the-middle attacks, downgrade attacks, or other cryptographic exploitation techniques that leverage the inconsistent cipher handling behavior.
The unspecified impact vector represents a significant concern for system administrators and security professionals, as the exact attack surface and potential consequences remain unclear without detailed analysis of the specific implementation details. However, the nature of cryptographic configuration flaws typically allows for various attack vectors including protocol downgrade attacks, where adversaries can force systems to use weaker cipher suites than intended. The vulnerability could enable attackers to exploit the parsing inconsistencies to manipulate TLS connections, potentially leading to data interception, authentication bypasses, or complete session compromise. According to ATT&CK framework, this vulnerability would map to T1566 (Phishing) and T1046 (Network Service Scanning) as attackers might use this weakness to establish more favorable conditions for further exploitation. The multi-keyword parsing context suggests that this issue could be particularly dangerous in environments where complex cipher configurations are used, such as enterprise applications or security appliances that rely on specific cryptographic policies.
Mitigation strategies for CVE-2015-3278 should focus on immediate patching of the nss_compat_ossl library to address the cipherstring parsing logic. System administrators should implement comprehensive monitoring for any unusual cipher suite selection patterns or connection failures that might indicate exploitation attempts. The remediation process should include thorough testing of all affected systems to ensure that the patched version properly validates cipherstring inputs and maintains consistent behavior across all cipher combinations. Organizations should also review their cryptographic configuration policies to ensure that cipherstring specifications are properly validated and that unnecessary complexity in multi-keyword configurations is minimized. Additionally, implementing network-based detection measures such as intrusion detection systems that monitor for anomalous cipher suite usage patterns can help identify potential exploitation attempts. The vulnerability highlights the critical importance of proper cryptographic library validation and the need for robust input sanitization in security-critical components that handle cryptographic parameters and configurations.