[draft] End of Support For Kerberos 4
Cesar Garcia
Cesar.Garcia at morganstanley.com
Fri Aug 20 16:44:06 EDT 2004
what are the timeframes for 1.4/1.5 (if known)?
On 08/20/04 16:19:43, Sam Hartman wrote:
> [Comments before I send this to kerberos-announce are welcome.]
>
> With the release of MIT Kerberos version 1.3, MIT began the process of
> ending support for version 4 of the Kerberos protocol. IN the 1.3
> release, we default to disabling Kerberos protocol version 4 on MIT
> KDCs.
>
> Now we announce the continuation of our plan to end support for
> Kerberos 4. This plan will continue in two phases. First, MIT is
> committed to including Kerberos 4 support in release 1.4 of MIT
> Kerberos. However we plan to remove Kerberos 4 support from some
> future version of MIT Kerberos; hopefully we will be able to remove
> Kerberos 4 support for the 1.5 release of MIT Kerberos.
>
> Secondly, MIT has ended development of Kerberos 4 except for two
> special projects. The first project is to merge the Kerberos 4
> implementation used on Windows into the main Kerberos 4 implementation
> used on Unix and the Mac. The second project is the eventual removal
> of all Kerberos 4 functionality. MIT will continue to provide
> critical security fixes for Kerberos 4, but routine bug fixing and
> feature enhancements are at an end.
>
>
> We recommend any sites that have not already done so begin a migration
> to Kerberos 5. Kerberos 5 provides support for strong encryption,
> extensibility, much better cross-vendor interoperability and ongoing
> development and enhancement.
>
> Over the past year, two developments have lead to the critical need to
> end support for Kerberos 4. The first is the NIST decision to end
> certification for the DES encryption system [1]. DES is the only
> encryption supported by Kerberos 4. Affording the equipment necessary
> to break DES encryption is within the means of many companies and all
> major governments. As such, DES cannot be considered secure for any
> long-term keys, especially including the ticket-granting key that is
> central to a Kerberos. Secondly, protocol flaws were discovered in
> Kerberos 4 [2]. These flaws make cross-realm authentication an
> unacceptable security risk for Kerberos 4 and call into question the
> security of the entire Kerberos 4 protocol.
>
>
> We wish you all the best of luck in your migration to Kerberos 5 and
> hope you enjoy the flexibility and power of the new protocol.
>
> References
>
> [1] http://csrc.ncsl.nist.gov/publications/nistbul/09-02itl.pdf
>
> [2] Tom Yu, Sam Hartman, and Ken Raeburn. The Perils of
> Unauthenticated Encryption: Kerberos Version 4. In Proceedings
> of the Network and Distributed Systems Security
> Symposium. The
> Internet Society, February 2004.
> (http://web.mit.edu/tlyu/papers/krb4peril-ndss04.pdf)
>
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