krb5-1.17.2 is released

Greg Hudson ghudson at
Tue Nov 17 20:03:15 EST 2020

Hash: SHA512

The MIT Kerberos Team announces the availability of MIT Kerberos 5
Release 1.17.2.  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 1.17.2 source from the
following URL:

(The distribution URL has changed from previous releases.  The same
contents are available at the old URL.)

The homepage for the krb5-1.17.2 release is:

Further information about Kerberos 5 may be found at the following

and at the MIT Kerberos Consortium web site:

Feedback based on experiences with the SPAKE pre-authentication
mechanism and the LMDB-based KDB module would be greatly appreciated,
as it will help us decide when these features are ready to become
defaults in a future release.  Please send feedback to
kerberos at

DES transition

The Data Encryption Standard (DES) is widely recognized as weak.  The
krb5-1.7 release contains measures to encourage sites to migrate away
from using single-DES cryptosystems.  Among these is a configuration
variable that enables "weak" enctypes, which defaults to "false"
beginning with krb5-1.8.

Major changes in 1.17.2 (2020-11-17)

This is a bug fix release.

* Fix a denial of service vulnerability when decoding Kerberos
  protocol messages.

* Fix a locking issue with the LMDB KDB module which could cause KDC
  and kadmind processes to lose access to the database.

* Fix an assertion failure when libgssapi_krb5 is repeatedly loaded
  and unloaded while libkrb5support remains loaded.

* Fix a null deference when processing a CAMMAC with an invalid
  service verifier.

Major changes in 1.17.1 (2019-12-11)

This is a bug fix release.

* Fix a bug preventing "addprinc -randkey -kvno" from working in

* Fix a bug preventing time skew correction from working when a KCM
  credential cache is used.

Major changes in 1.17 (2019-01-08)

Administrator experience:

* A new Kerberos database module using the Lightning Memory-Mapped
  Database library (LMDB) has been added.  The LMDB KDB module should
  be more performant and more robust than the DB2 module, and may
  become the default module for new databases in a future release.

* "kdb5_util dump" will no longer dump policy entries when specific
  principal names are requested.

Developer experience:

* The new krb5_get_etype_info() API can be used to retrieve enctype,
  salt, and string-to-key parameters from the KDC for a client

* The new GSS_KRB5_NT_ENTERPRISE_NAME name type allows enterprise
  principal names to be used with GSS-API functions.

* KDC and kadmind modules which call com_err() will now write to the
  log file in a format more consistent with other log messages.

* Programs which use large numbers of memory credential caches should
  perform better.

Protocol evolution:

* The SPAKE pre-authentication mechanism is now supported.  This
  mechanism protects against password dictionary attacks without
  requiring any additional infrastructure such as certificates.  SPAKE
  is enabled by default on clients, but must be manually enabled on
  the KDC for this release.

* PKINIT freshness tokens are now supported.  Freshness tokens can
  protect against scenarios where an attacker uses temporary access to
  a smart card to generate authentication requests for the future.

* Password change operations now prefer TCP over UDP, to avoid
  spurious error messages about replays when a response packet is

* The KDC now supports cross-realm S4U2Self requests when used with a
  third-party KDB module such as Samba's.  The client code for
  cross-realm S4U2Self requests is also now more robust.

User experience:

* The new ktutil addent -f flag can be used to fetch salt information
  from the KDC for password-based keys.

* The new kdestroy -p option can be used to destroy a credential cache
  within a collection by client principal name.

* The Kerberos man page has been restored, and documents the
  environment variables that affect programs using the Kerberos

Code quality:

* Python test scripts now use Python 3.

* Python test scripts now display markers in verbose output, making it
  easier to find where a failure occurred within the scripts.

* The Windows build system has been simplified and updated to work
  with more recent versions of Visual Studio.  A large volume of
  unused Windows-specific code has been removed.  Visual Studio 2013
  or later is now required.

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