CVE-2016-0923 in RSA BSAFE Micro Edition Suite
Summary
by MITRE
The client in EMC RSA BSAFE Micro Edition Suite (MES) 4.0.x before 4.0.9 and 4.1.x before 4.1.5 places the weakest algorithms first in a signature-algorithm list transmitted to a server, which makes it easier for remote attackers to defeat cryptographic protection mechanisms by leveraging server behavior in which the first algorithm is used.
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Analysis
by VulDB Data Team • 09/16/2022
The vulnerability identified as CVE-2016-0923 affects the EMC RSA BSAFE Micro Edition Suite version 4.0.x prior to 4.0.9 and 4.1.x prior to 4.1.5, representing a significant weakness in cryptographic protocol implementation that undermines security assurances. This issue resides within the client-side component of the suite, specifically in how it handles signature algorithm negotiation during cryptographic communications with servers. The flaw manifests when the client transmits a list of supported signature algorithms to the server, with the weakest cryptographic algorithms positioned at the beginning of this list. This particular implementation pattern creates a dangerous scenario where servers that follow standard practices of selecting the first available algorithm from the list will automatically choose the least secure option, thereby compromising the overall cryptographic strength of the communication channel.
The technical nature of this vulnerability aligns with CWE-327, which addresses the use of weak cryptographic algorithms, and more specifically with CWE-326, which deals with the use of insecure or weak cryptographic algorithms. The flaw operates at the protocol level where cryptographic algorithm preference ordering is implemented, creating a downgrade attack vector that adversaries can exploit to force the system into using weaker encryption methods. This behavior represents a fundamental misconfiguration in the cryptographic handshake process, where the client's algorithm preference list does not prioritize security considerations over compatibility or other factors. The vulnerability essentially creates a scenario where the security of the entire cryptographic exchange becomes dependent on the server's implementation choices rather than enforcing strong cryptographic standards through proper client-side configuration.
From an operational perspective, this vulnerability enables remote attackers to systematically weaken cryptographic protections by leveraging the predictable behavior of servers that select the first algorithm in the list. The impact extends beyond simple encryption downgrade, as it can potentially allow attackers to perform man-in-the-middle attacks, intercept communications, and compromise sensitive data exchanges that rely on the cryptographic integrity provided by the RSA BSAFE Micro Edition Suite. The vulnerability is particularly concerning because it affects a widely used cryptographic library that many applications depend upon for secure communications, making the potential attack surface substantial. Organizations using affected versions may experience unauthorized access to encrypted communications, data breaches, and loss of confidentiality that could affect regulatory compliance and security certifications.
The mitigation strategy for this vulnerability requires immediate patching of affected systems to versions 4.0.9 or later for 4.0.x releases and 4.1.5 or later for 4.1.x releases, as provided by EMC. Additionally, administrators should implement proper cryptographic algorithm preference ordering that prioritizes strong algorithms over weak ones, ensuring that the first algorithm in any negotiated list is at least of acceptable security strength. Network monitoring should be enhanced to detect unusual cryptographic algorithm selections, and security policies should be updated to enforce minimum cryptographic strength requirements. This vulnerability demonstrates the critical importance of proper cryptographic protocol implementation and highlights the dangers of algorithm preference ordering that does not consider security implications over other operational factors. The remediation process should also include comprehensive testing of cryptographic configurations to ensure that the patched versions properly implement secure algorithm selection and that no other components within the cryptographic ecosystem are similarly vulnerable to algorithm downgrade attacks.