Moderate CentOS krb5 Security Update


krb5-devel-1.13.2-10.el7.i686.rpm, krb5-devel-1.13.2-10.el7.x86_64.rpm, krb5-libs-1.13.2-10.el7.i686.rpm, krb5-libs-1.13.2-10.el7.x86_64.rpm, krb5-pkinit-1.13.2-10.el7.x86_64.rpm, krb5-server-1.13.2-10.el7.x86_64.rpm, krb5-server-ldap-1.13.2-10.el7.x86_64.rpm, krb5-workstation-1.13.2-10.el7.x86_64.rpm,
2018-01-18 11:11
2017-07-27 19:10
2017-04-01 19:09
2017-01-05 20:13


Updated krb5 packages that fix two security issues, several bugs, and add
various enhancements are now available for Red Hat Enterprise Linux 7.

Red Hat Product Security has rated this update as having Moderate security
impact. Common Vulnerability Scoring System (CVSS) base scores, which give
detailed severity ratings, are available for each vulnerability from the
CVE links in the References section.

Kerberos is a network authentication system, which can improve the security
of your network by eliminating the insecure practice of sending passwords
over the network in unencrypted form. It allows clients and servers to
authenticate to each other with the help of a trusted third party, the
Kerberos key distribution center (KDC).

It was found that the krb5_read_message() function of MIT Kerberos did not
correctly sanitize input, and could create invalid krb5_data objects.
A remote, unauthenticated attacker could use this flaw to crash a Kerberos
child process via a specially crafted request. (CVE-2014-5355)

A flaw was found in the OTP kdcpreauth module of MIT kerberos.
An unauthenticated remote attacker could use this flaw to bypass the
requires_preauth flag on a client principal and obtain a ciphertext
encrypted in the principal's long-term key. This ciphertext could be used
to conduct an off-line dictionary attack against the user's password.

The krb5 packages have been upgraded to upstream version 1.13.2, which
provides a number of bug fixes and enhancements over the previous version.

Notably, this update fixes the following bugs:

* Previously, the RADIUS support (libkrad) in krb5 was sending krb5
authentication for Transmission Control Protocol (TCP) transports multiple
times, accidentally using a code path intended to be used only for
unreliable transport types, for example User Datagram Protocol (UDP)
transports. A patch that fixes the problem by disabling manual retries for
reliable transports, such as TCP, has been applied, and the correct code
path is now used in this situation. (BZ#1251586)

* Attempts to use Kerberos single sign-on (SSO) to access SAP NetWeaver
systems sometimes failed. The SAP NetWeaver developer trace displayed the
following error message:

No credentials were supplied, or the credentials were
unavailable or inaccessible
Unable to establish the security context

Querying SSO credential lifetime has been modified to trigger credential
acquisition, thus preventing the error from occurring. Now, the user can
successfully use Kerberos SSO for accessing SAP NetWeaver systems.

All krb5 users are advised to upgrade to these updated packages, which
correct these issues and add these enhancements.
Please see

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Affected package information

Release Package Patched in
7 krb5-devel krb5-devel-1.13.2-10.el7.i686.rpm
krb5-devel krb5-devel-1.13.2-10.el7.x86_64.rpm
krb5-libs krb5-libs-1.13.2-10.el7.i686.rpm
krb5-libs krb5-libs-1.13.2-10.el7.x86_64.rpm
krb5-pkinit krb5-pkinit-1.13.2-10.el7.x86_64.rpm
krb5-server krb5-server-1.13.2-10.el7.x86_64.rpm
krb5-server-ldap krb5-server-ldap-1.13.2-10.el7.x86_64.rpm
krb5-workstation krb5-workstation-1.13.2-10.el7.x86_64.rpm