CVE-2016-1000341: Timing Attack vulnerability in bcprov-jdk14 (Maven)

What is CVE-2016-1000341 About?

This is a Timing Attack vulnerability in the Bouncy Castle JCE Provider, affecting versions 1.55 and earlier, during DSA signature generation. Successful exploitation can reveal the signer's private key by observing signature timings, making it an information disclosure risk, and exploitation depends on precise timing observations.

Affected Software

org.bouncycastle:bcprov-jdk14
- <1.56
org.bouncycastle:bcprov-jdk15
- <1.56
org.bouncycastle:bcprov-jdk15on
- <1.56

Technical Details

The vulnerability in Bouncy Castle JCE Provider (version 1.55 and earlier) concerns the DSA signature generation process, specifically a lack of blinding. Blinding is a technique used in cryptography to introduce randomness into cryptographic operations to prevent timing attacks. Without proper blinding during DSA signature generation, the execution time of the signature process can vary based on properties of the k value (the ephemeral private key used in each DSA signature). If an attacker can closely observe and measure these timing differences, they might be able to deduce information about the 'k' value, and subsequently, through mathematical analysis, reconstruct the static private key used for signing. This constitutes an information disclosure via a side-channel attack.

What is the Impact of CVE-2016-1000341?

Successful exploitation may allow attackers to disclose sensitive cryptographic private keys, compromising the authenticity and integrity of digital signatures.

What is the Exploitability of CVE-2016-1000341?

Exploitation requires the attacker to be able to accurately measure the time it takes for the vulnerable Bouncy Castle implementation to generate DSA signatures. This often implies local access to the system or a network position that allows for very precise timing measurements, making it a sophisticated attack. There are no explicit authentication or privilege requirements for influencing the signature process itself if the attacker can submit data for signing and observe timings. The complexity is high, as it requires specialized knowledge of timing attacks, statistical analysis, and cryptographic protocols. Risk factors include systems where DSA signatures are frequently generated and executed on shared hardware or within environments where precise timing measurements are feasible for an attacker.

What are the Known Public Exploits?

PoC Author	Link	Commentary
No known exploits

What are the Available Fixes for CVE-2016-1000341?

Available Upgrade Options

org.bouncycastle:bcprov-jdk14
- <1.56 → Upgrade to 1.56
org.bouncycastle:bcprov-jdk15on
- <1.56 → Upgrade to 1.56
org.bouncycastle:bcprov-jdk15
- <1.56 → Upgrade to 1.56

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Additional Resources

What are Similar Vulnerabilities to CVE-2016-1000341?

Similar Vulnerabilities: CVE-2016-1000346 , CVE-2015-7940 , CVE-2017-6167 , CVE-2018-5383 , CVE-2020-24905

CVE-2016-1000341 Timing Attack vulnerability in bcprov-jdk14 (Maven)