CVE-2014-4192 in RSA BSAFE-C Toolkits
Summary
by MITRE
The Dual_EC_DRBG implementation in EMC RSA BSAFE-C Toolkits (aka Share for C and C++) processes certain requests for output bytes by considering only the requested byte count and not the use of cached bytes, which makes it easier for remote attackers to obtain plaintext from TLS sessions by recovering the algorithm s inner state, a different issue than CVE-2007-6755.
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Analysis
by VulDB Data Team • 03/04/2018
The vulnerability described in CVE-2014-4192 represents a critical weakness in the cryptographic implementation of EMC RSA BSAFE-C Toolkits, specifically within the Dual_EC_DRBG pseudorandom number generator algorithm. This flaw exists in the Share for C and C++ versions of the toolkit and demonstrates a fundamental design error in how the random number generation process handles cached data. The issue manifests when the system processes requests for output bytes, where it fails to properly account for previously cached values in its internal state management. This oversight creates a predictable pattern in the random number generation sequence that significantly weakens the cryptographic security of the system.
The technical implementation flaw stems from the Dual_EC_DRBG algorithm's inherent mathematical properties combined with the specific implementation error in the BSAFE-C toolkit. When the system generates random bytes for cryptographic operations such as TLS session encryption, it should maintain proper state tracking of both requested and cached outputs. However, the flawed implementation only considers the immediately requested byte count without properly accounting for the cached bytes that may have been previously generated and stored. This creates a scenario where an attacker can potentially reconstruct the internal state of the random number generator through careful analysis of the output patterns, particularly when observing multiple consecutive requests or when the system's state transitions are predictable.
The operational impact of this vulnerability extends beyond simple random number generation failures and directly compromises the security of TLS communications. Remote attackers can exploit this weakness to recover plaintext data from TLS sessions by reconstructing the algorithm's internal state, effectively breaking the encryption that protects sensitive communications. This vulnerability represents a significant downgrade in security posture for any system utilizing the affected toolkit, as it allows attackers to potentially decrypt communications that should remain protected. The attack vector is particularly concerning because it operates at the cryptographic algorithm level, making it difficult to detect through traditional network monitoring approaches and potentially allowing for undetected data exfiltration.
The weakness aligns with several cybersecurity frameworks and threat models, particularly those addressing cryptographic implementation flaws and random number generator vulnerabilities. This vulnerability maps to CWE-330, which describes insufficient entropy in random number generators, and relates to ATT&CK technique T1583.001 for obtaining credentials through cryptographic attacks. The flaw demonstrates poor adherence to cryptographic best practices and highlights the importance of proper state management in cryptographic implementations. Organizations using this toolkit face significant risk of man-in-the-middle attacks, session hijacking, and data interception, particularly in environments where TLS-protected communications are critical for security. The vulnerability's relationship to CVE-2007-6755 further emphasizes the ongoing challenges with Dual_EC_DRBG implementations and the persistent security issues associated with this particular algorithm design.
Mitigation strategies should include immediate replacement of the vulnerable toolkit with a secure alternative that implements cryptographically secure random number generation algorithms. Organizations must also implement comprehensive monitoring for unusual patterns in random number generation that might indicate exploitation attempts. The affected systems should undergo thorough security audits to identify any potential compromise from prior exploitation, and all TLS communications should be reviewed for possible data leakage. Additionally, cryptographic libraries should be updated to versions that do not rely on the vulnerable Dual_EC_DRBG algorithm, and security teams should implement proper entropy monitoring to detect similar implementation flaws in other cryptographic components. Regular security assessments should be conducted to ensure that all cryptographic implementations properly manage internal state and maintain adequate entropy levels throughout their operational lifecycle.