krb5-1.7 is released

Tom Yu tlyu at MIT.EDU
Tue Jun 2 11:24:59 EDT 2009

Hash: SHA1

The MIT Kerberos Team announces the availability of MIT Kerberos 5
Release 1.7.  Please see below for a list of some major changes
included, or consult the README file in the source tree for a more
detailed list of significant changes.


You may retrieve the Kerberos 5 Release 1.7 source from the
following URL:

The homepage for the krb5-1.7 release is:

Further information about Kerberos 5 may be found at the following

and at the MIT Kerberos Consortium web site:

DES transition

The Data Encryption Standard (DES) is widely recognized as weak.  The
krb5-1.7 release will contain measures to encourage sites to migrate
away from using single-DES cryptosystems.  Among these is a
configuration variable that enables "weak" enctypes, but will default
to "false" in the future.  Additional migration aids are planned for
future releases.

Major changes in 1.7

The krb5-1.7 release contains a large number of changes, featuring
improvements in the following broad areas:

* Compatibility with Microsoft Windows

* Administrator experience

* User experience

* Code quality

* Protocol evolution

Compatibility with Microsoft Windows:

* Follow client principal referrals in the client library when
  obtaining initial tickets.

* KDC can issue realm referrals for service principals based on domain

* Extensions supporting DCE RPC, including three-leg GSS context setup
  and unencapsulated GSS tokens inside SPNEGO.

* Microsoft GSS_WrapEX, implemented using the gss_iov API, which is
  similar to the equivalent SSPI functionality.  This is needed to
  support some instances of DCE RPC.

* NTLM recognition support in GSS-API, to facilitate dropping in an
  NTLM implementation for improved compatibility with older releases
  of Microsoft Windows.

* KDC support for principal aliases, if the back end supports them.
  Currently, only the LDAP back end supports aliases.

* Support Microsoft set/change password (RFC 3244) protocol in

* Implement client and KDC support for GSS_C_DELEG_POLICY_FLAG, which
  allows a GSS application to request credential delegation only if
  permitted by KDC policy.

Administrator experience:

* Install header files for the administration API, allowing
  third-party software to manipulate the KDC database.

* Incremental propagation support for the KDC database.

* Master key rollover support, making it easier to change master key
  passwords or encryption types.

* New libdefaults configuration variable "allow_weak_crypto".  NOTE:
  Currently defaults to "true", but may default to "false" in a future
  release.  Setting this variable to "false" will have the effect of
  removing weak enctypes (currently defined to be all single-DES
  enctypes) from permitted_enctypes, default_tkt_enctypes, and

User experience:

* Provide enhanced GSS-API error message including supplementary
  details about error conditions.

* In the replay cache, use a hash over the complete ciphertext to
  avoid false-positive replay indications.

Code quality:

* Replace many uses of "unsafe" string functions.  While most of these
  instances were innocuous, they impeded efficient automatic and
  manual static code analysis.

* Fix many instances of resource leaks and similar bugs identified by
  static analysis tools.

* Fix CVE-2009-0844, CVE-2009-0845, CVE-2009-0846, CVE-2009-0847 --
  various vulnerabilities in SPNEGO and ASN.1 code.

Protocol evolution:

* Remove support for version 4 of the Kerberos protocol (krb4).

* Encryption algorithm negotiation (RFC 4537), allowing clients and
  application services to negotiate stronger encryption than their KDC

* Flexible Authentication Secure Tunneling (FAST), a preauthentiation
  framework that can protect the AS exchange from dictionary attacks
  on weak user passwords.
Version: GnuPG v1.4.8 (SunOS)

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