Incorrect access control in Yubico OTP functionality of the YubiKey hardware tokens along with the Yubico OTP validation server. The Yubico OTP supposedly creates hardware bound second factor credentials. When a user reprograms the OTP functionality by "writing" it on a token using the Yubico Personalization Tool, they can then upload the new configuration to Yubicos OTP validation servers. NOTE: the vendor disputes this because there is no way for a YubiKey device to prevent a user from deciding that a secret value, which is imported into the device, should also be stored elsewhere