CVE-2016-1000341 in JCE Provider
Summary
by MITRE
In the Bouncy Castle JCE Provider version 1.55 and earlier DSA signature generation is vulnerable to timing attack. Where timings can be closely observed for the generation of signatures, the lack of blinding in 1.55, or earlier, may allow an attacker to gain information about the signature's k value and ultimately the private value as well.
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Analysis
by VulDB Data Team • 09/13/2025
The vulnerability identified as CVE-2016-1000341 affects the Bouncy Castle JCE Provider version 1.55 and earlier implementations, specifically targeting DSA signature generation mechanisms. This weakness represents a critical security flaw that undermines the cryptographic integrity of digital signatures through timing side-channel attacks. The Bouncy Castle library serves as a widely-used cryptographic implementation for java applications, making this vulnerability particularly concerning for systems relying on secure digital signatures for authentication and data integrity.
The technical flaw stems from the absence of cryptographic blinding in the DSA signature generation process within the affected versions. Blinding is a fundamental cryptographic technique designed to prevent timing attacks by ensuring that the computational operations take constant time regardless of the input values. Without this protection, the signature generation process exhibits variable execution times that correlate with the private key bits being processed. This timing variation creates a side-channel vulnerability that allows attackers to observe and analyze the execution patterns during signature creation.
From an operational impact perspective, this vulnerability enables attackers to perform sophisticated timing analysis attacks that can extract the secret k value used in DSA signatures. The k value represents a critical component in the DSA algorithm that must remain secret to maintain the security of the entire signature scheme. When an attacker successfully determines the k value through timing observations, they can subsequently compute the private key, effectively compromising the entire cryptographic system. This represents a complete breakdown of the security model, as the private key can be derived from multiple signatures generated under similar timing conditions.
The vulnerability aligns with CWE-326, which addresses the weakness of insufficient cryptographic randomness, and relates to ATT&CK technique T1552.004 for unsecured credentials storage, though specifically in the context of cryptographic implementation weaknesses. Organizations using affected Bouncy Castle versions face significant risk, particularly in environments where signature generation occurs under conditions where timing observations are feasible. The vulnerability is especially dangerous in networked environments where attackers can monitor signature generation processes over multiple requests, potentially accumulating enough timing data to perform successful key recovery attacks.
Mitigation strategies should focus on immediate upgrades to Bouncy Castle version 1.56 or later, which includes proper blinding implementations for DSA signature generation. Organizations should also implement monitoring solutions to detect unusual timing patterns in cryptographic operations and consider additional cryptographic protections such as using ECDSA instead of DSA where possible. The remediation process must include thorough testing of applications to ensure compatibility with updated cryptographic libraries while maintaining the security posture against timing attacks.