Yubico YubiKey 5 Series devices with firmware before 5.7.0 and YubiHSM 2 devices with firmware before 2.4.0 allow an ECDSA secret-key extraction attack (that requires physical access and expensive equipment) in which an electromagnetic side channel is present because of a non-constant-time modular inversion for the Extended Euclidean Algorithm, aka the EUCLEAK issue. Other uses of an Infineon cryptographic library may also be affected.

References

• MISC:https://arstechnica.com/security/2024/09/yubikeys-are-vulnerable-to-cloning-attacks-thanks-to-newly-discovered-side-channel/
• MISC:https://news.ycombinator.com/item?id=41434500
• MISC:https://ninjalab.io/eucleak/
• MISC:https://ninjalab.io/wp-content/uploads/2024/09/20240903_eucleak.pdf
• MISC:https://support.yubico.com/hc/en-us/articles/15705749884444
• MISC:https://www.yubico.com/support/security-advisories/ysa-2024-03/