krb5: issues in OTP and PKINIT kdcpreauth modules leading to requires_preauth bypass

A flaw was found in the OTP kdcpreauth module of MIT Kerberos. A remote attacker could use this flaw to bypass the requirespreauth flag on a client principal and obtain a ciphertext encrypted in the principal's long-term key. This ciphertext could be used to conduct an off-line dictionary attack...