Kyber, a quantum-safe encryption mechanism, faces vulnerabilities collectively known as KyberSlash, allowing potential recovery of secret keys. These flaws arise from timing-based attacks during certain division operations in the decapsulation process, allowing attackers to exploit execution time and compromise encryption. Projects like Mullvad VPN and Signal messenger, utilizing Kyber implementations, become susceptible to these attacks. Although some affected projects have received patches, the impact of KyberSlash varies across implementations, emphasizing the need for upgrading to secure versions and implementing additional security measures.
The KyberSlash vulnerabilities, named KyberSplash1 and KyberSplash2, were discovered by researchers at Cryspen, a provider of verification tools and mathematically proven software. The flaws enable attackers to measure timing differences in multiple operation requests towards the same key pair, potentially leading to the gradual computation of the secret key. The discovery prompted developers to release patches, with the first patch addressing KyberSplash1 on December 1, 2023, and the second for KyberSplash2 on December 30, 2023. Cryspen took a more public approach on December 15, notifying impacted projects to upgrade their Kyber implementations.
As of January 2, 2024, a list of projects impacted by KyberSlash was identified, with various fixing statuses. While some projects are fully patched, others have only addressed specific vulnerabilities, and a few remain unpatched. The severity of KyberSlash lies in the potential leakage of secret keys, though the extent of vulnerability depends on the Kyber implementation and additional security measures in place. The complexity of repercussions underscores the importance of vigilance, upgrading to secure versions, and implementing robust security measures to safeguard against these quantum-safe encryption vulnerabilities.