Kerberos: The Network Authentication Protocol

JPEG of Kerberos

Recent News

Old news is archived.

22 Oct 2007 - Kerberos for Windows 3.2.2 is released

MIT Kerberos for Windows 3.2.2 is released.

22 Oct 2007 - krb5-1.6.3 is released

The krb5-1.6.3 source release is now available.

04 Sep 2007 - MITKRB5-SA-2007-006

kadmind vulnerable to RPC lib buffer overflow, uninitialized pointer

10 Jul 2007 - krb5-1.5.4 is released

The krb5-1.5.4 source release is now available.

26 Jun 2007 - two security advisories released

MITKRB5-SA-2007-004
MITKRB5-SA-2007-005
or see the advisories index

03 Apr 2007 - three security advisories released

See the advisories index

09 Jan 2007 - MITKRB5-SA-2006-003

kadmind frees uninitialized pointers. See advisories index or advisory text.

09 Jan 2007 - MITKRB5-SA-2006-002

kadmind calls uninitialized function pointers. See advisories index or advisory text.

What is Kerberos?

Kerberos is a network authentication protocol. It is designed to provide strong authentication for client/server applications by using secret-key cryptography. A free implementation of this protocol is available from the Massachusetts Institute of Technology. Kerberos is available in many commercial products as well.

The Internet is an insecure place. Many of the protocols used in the Internet do not provide any security. Tools to "sniff" passwords off of the network are in common use by malicious hackers. Thus, applications which send an unencrypted password over the network are extremely vulnerable. Worse yet, other client/server applications rely on the client program to be "honest" about the identity of the user who is using it. Other applications rely on the client to restrict its activities to those which it is allowed to do, with no other enforcement by the server.

Some sites attempt to use firewalls to solve their network security problems. Unfortunately, firewalls assume that "the bad guys" are on the outside, which is often a very bad assumption. Most of the really damaging incidents of computer crime are carried out by insiders. Firewalls also have a significant disadvantage in that they restrict how your users can use the Internet. (After all, firewalls are simply a less extreme example of the dictum that there is nothing more secure then a computer which is not connected to the network --- and powered off!) In many places, these restrictions are simply unrealistic and unacceptable.

Kerberos was created by MIT as a solution to these network security problems. The Kerberos protocol uses strong cryptography so that a client can prove its identity to a server (and vice versa) across an insecure network connection. After a client and server has used Kerberos to prove their identity, they can also encrypt all of their communications to assure privacy and data integrity as they go about their business.

Kerberos is freely available from MIT, under copyright permissions very similar those used for the BSD operating system and the X Window System. MIT provides Kerberos in source form so that anyone who wishes to use it may look over the code for themselves and assure themselves that the code is trustworthy. In addition, for those who prefer to rely on a professionally supported product, Kerberos is available as a product from many different vendors.

In summary, Kerberos is a solution to your network security problems. It provides the tools of authentication and strong cryptography over the network to help you secure your information systems across your entire enterprise. We hope you find Kerberos as useful as it has been to us. At MIT, Kerberos has been invaluable to our Information/Technology architecture.


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