Goal and Drawbacks of Kerberos

Goal and Drawbacks of Kerberos

The primary goal of Kerberos is to ensure private communications between systems over a network. However, in managing the encryption keys, it acts to authenticate each of the principals in the communication based on the possession of the secret key, which allows access to the session key. Kerberos is an elegant solution and used in many platforms as the basis for broad authentication processes.

Drawbacks of Kerberos

No solution is perfect, and there are some issues related to using Kerberos.

The security of the entire system depends on careful implementation; enforcing limited lifetimes for authentication credentials helps minimize the threats of replayed credentials. The KDC must be physically secured and protected, not permitting any non-Kerberos activity.

The KDC can be a single point of failure and therefore should be supported by backup and continuity plans. It is not uncommon for there to be several KDCs in Kerberos architecture. Each KDC shares principal information, such as keys, to support the infrastructure if one of the systems fails. In Microsoft Windows-based Active Directory Domain Services (ADDS) environments, all domain controllers are KDC's, thus creating an architecture where there is no single point of failure due to a KDC being knocked offline or becoming unavailable.

The length of the keys (secret and session) is very important. For example, if the key is too short, it is vulnerable to brute force attacks. If it is too long, systems can be overloaded with encrypting and decrypting tickets and network data. Finally, the Achilles' heel of Kerberos is that encryption processes are ultimately based on passwords. Therefore, it can fall victim to traditional password-guessing attacks.