Kerberos

• A dictionary attack on the response from a Kerberos server is possible since the ticket-granting-ticket is returned encrypted using the user's password as a key. The response to the user contains readable information. An attacker may capture this response and perform a dictionary attack on it until readable plaintext is produced.

• Tickets are kept in the memory on both clients and servers. The protection of these tickets is then left to the strength of the protection of the systems.

• Kerberos can be susceptible to a single-point-of-failure attack since both clients and servers must rely on a Kerberos server to be granted and to verify tickets. The Kerberos server's ability to authenticate users with trust essentially relies on one master key.