CVE-2024-14041 | HackTesting

In Bouncy Castle for Java from 1.73 to before 1.78, three ML-KEM (CRYSTALS-Kyber) routines divided secret-derived polynomial coefficients by the modulus q: Poly.toMsg, which decodes the decrypted message, and the ciphertext compression routines Poly.compressPoly and PolyVec.compressPolyVec. An attacker able to measure the timing of a large number of decapsulations performed with the same long-term private key can recover that key. These are the KyberSlash1 (Poly.toMsg) and KyberSlash2 (ciphertext compression) divisions. Compression performed during encapsulation operates on values that become the public ciphertext and is not affected.

Credits

The Robusta team: Deepak Bhargavan Pillai, Anirban Chakraborty, Chitchanok Chuengsatiansup, Matthew Roughan, Peter Schwabe, and Yuval Yarom

The KyberSlash authors: Daniel J. Bernstein, Karthikeyan Bhargavan, Shivam Bhasin, Anupam Chattopadhyay, Tee Kiah Chia, Matthias J. Kannwischer, Franziskus Kiefer, Thales Paiva, Prasanna Ravi and Goutam Tamvada.

References

https://github.com/bcgit/bc-java/wiki/CVE-2024-14041

https://github.com/bcgit/bc-java/commit/5adb2c5c5b462a332b01a012bea0784b40b904e5

https://github.com/bcgit/bc-java/commit/1590247178f2280defa36421475f015175dfbe9e

https://kyberslash.cr.yp.to/