Date:         Wed, 7 Apr 2010 13:30:42 -0500
Reply-To:     Troy Dawson 
Sender:       Security Errata for Scientific Linux
              
From:         Troy Dawson 
Subject:      Security ERRATA Important: krb5 on SL5.x i386/x86_64
Comments: To: "scientific-linux-errata@fnal.gov"
          

Synopsis:	Important: krb5 security and bug fix update
Issue date:	2010-04-06
CVE Names:	CVE-2010-0629

A use-after-free flaw was discovered in the MIT Kerberos administration
daemon, kadmind. A remote, authenticated attacker could use this flaw to
crash the kadmind daemon. Administrative privileges are not required to
trigger this flaw, as any realm user can request information about their
own principal from kadmind. (CVE-2010-0629)

This update also fixes the following bug:

* when a Kerberos client seeks tickets for use with a service, it must
contact the Key Distribution Center (KDC) to obtain them. The client 
must also determine which realm the service belongs to and it typically 
does this with a combination of client configuration detail, DNS 
information and guesswork.

If the service belongs to a realm other than the client's, cross-realm
authentication is required. Using a combination of client configuration 
and guesswork, the client determines the trust relationship sequence 
which forms the trusted path between the client's realm and the 
service's realm. This may include one or more intermediate realms.

Anticipating the KDC has better knowledge of extant trust relationships,
the client then requests a ticket from the service's KDC, indicating it
will accept guidance from the service's KDC by setting a special flag in
the request. A KDC which recognizes the flag can, at its option, return 
a ticket-granting ticket for the next realm along the trust path the 
client should be following.

If the ticket-granting ticket returned by the service's KDC is for use 
with a realm the client has already determined was in the trusted path, 
the client accepts this as an optimization and continues. If, however, 
the ticket is for use in a realm the client is not expecting, the client
responds incorrectly: it treats the case as an error rather than 
continuing along the path suggested by the service's KDC.

For this update, the krb5 1.7 modifications which allow the client to 
trust such KDCs to send them along the correct path, resulting in the 
client obtaining the tickets it originally desired, were backported to 
krb 1.6.1 (the version shipped with Scientific Linux 5.5). (BZ#578540)

All running KDC services must be restarted for the update to take effect.

SL 5.x

     SRPMS:
krb5-1.6.1-36.el5_5.2.src.rpm
     i386:
krb5-devel-1.6.1-36.el5_5.2.i386.rpm
krb5-libs-1.6.1-36.el5_5.2.i386.rpm
krb5-server-1.6.1-36.el5_5.2.i386.rpm
krb5-workstation-1.6.1-36.el5_5.2.i386.rpm
     x86_64:
krb5-devel-1.6.1-36.el5_5.2.i386.rpm
krb5-devel-1.6.1-36.el5_5.2.x86_64.rpm
krb5-libs-1.6.1-36.el5_5.2.i386.rpm
krb5-libs-1.6.1-36.el5_5.2.x86_64.rpm
krb5-server-1.6.1-36.el5_5.2.x86_64.rpm
krb5-workstation-1.6.1-36.el5_5.2.x86_64.rpm

-Connie Sieh
-Troy Dawson