(Red Hat Issues Fix) MIT Kerberos Multiple Memory Errors Let Remote Users Deny Service
SecurityTracker Alert ID: 1030859|
SecurityTracker URL: http://securitytracker.com/id/1030859
(Links to External Site)
Date: Sep 17 2014
Denial of service via network, Execution of arbitrary code via network, User access via network|
Fix Available: Yes Vendor Confirmed: Yes |
Version(s): prior to 5-1.12.2|
Several vulnerabilities were reported in MIT Kerberos. A remote user can cause denial of service conditions.|
A remote user with the ability to inject packets into a valid GSSAPI application session can trigger a buffer overread and cause the application to crash [CVE-2014-4341].
A remote user with the ability to inject packets into a valid GSSAPI application session can trigger a buffer overread or null pointer dereference and cause the application to crash [CVE-2014-4342].
A remote user with the ability to spoof packets from a GSSAPI application acceptor to trigger a double-free memory error and cause the target application to crash or potentially execute arbitrary code [CVE-2014-4343].
A remote authenticated or partially authenticated user can send specially crafted data during a SPNEGO negotiation to trigger a null pointer dereference and cause the target application to crash [CVE-2014-4344].
A remote user can cause the target application to crash or potentially execute arbitrary code.|
Red Hat has issued a fix for CVE-2014-4341 and CVE-2014-4344.|
The Red Hat advisory is available at:
Vendor URL: web.mit.edu/kerberos/ (Links to External Site)
Access control error, Boundary error, State error|
|Underlying OS: Linux (Red Hat Enterprise)|
|Underlying OS Comments: 5|
This archive entry is a follow-up to the message listed below.|
Source Message Contents
Subject: [RHSA-2014:1245-01] Moderate: krb5 security and bug fix update|
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Red Hat Security Advisory
Synopsis: Moderate: krb5 security and bug fix update
Advisory ID: RHSA-2014:1245-01
Product: Red Hat Enterprise Linux
Advisory URL: https://rhn.redhat.com/errata/RHSA-2014-1245.html
Issue date: 2014-09-16
CVE Names: CVE-2013-1418 CVE-2013-6800 CVE-2014-4341
Updated krb5 packages that fix multiple security issues and two bugs are
now available for Red Hat Enterprise Linux 5.
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.
2. Relevant releases/architectures:
Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64
Red Hat Enterprise Linux Desktop (v. 5 client) - i386, x86_64
Red Hat Enterprise Linux Desktop Workstation (v. 5 client) - i386, x86_64
Kerberos is an authentication system which allows clients and services to
authenticate to each other with the help of a trusted third party, a
Kerberos Key Distribution Center (KDC).
It was found that if a KDC served multiple realms, certain requests could
cause the setup_server_realm() function to dereference a NULL pointer.
A remote, unauthenticated attacker could use this flaw to crash the KDC
using a specially crafted request. (CVE-2013-1418, CVE-2013-6800)
A NULL pointer dereference flaw was found in the MIT Kerberos SPNEGO
acceptor for continuation tokens. A remote, unauthenticated attacker could
use this flaw to crash a GSSAPI-enabled server application. (CVE-2014-4344)
A buffer over-read flaw was found in the way MIT Kerberos handled certain
requests. A man-in-the-middle attacker with a valid Kerberos ticket who is
able to inject packets into a client or server application's GSSAPI session
could use this flaw to crash the application. (CVE-2014-4341)
This update also fixes the following bugs:
* Prior to this update, the libkrb5 library occasionally attempted to free
already freed memory when encrypting credentials. As a consequence, the
calling process terminated unexpectedly with a segmentation fault.
With this update, libkrb5 frees memory correctly, which allows the
credentials to be encrypted appropriately and thus prevents the mentioned
* Previously, when the krb5 client library was waiting for a response from
a server, the timeout variable in certain cases became a negative number.
Consequently, the client could enter a loop while checking for responses.
With this update, the client logic has been modified and the described
error no longer occurs. (BZ#1089732)
All krb5 users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. After installing the
updated packages, the krb5kdc daemon will be restarted automatically.
Before applying this update, make sure all previously released errata
relevant to your system have been applied.
This update is available via the Red Hat Network. Details on how to use the
Red Hat Network to apply this update are available at
5. Bugs fixed (https://bugzilla.redhat.com/):
1026942 - CVE-2013-1418 krb5: multi-realm KDC null dereference leads to crash
1031499 - CVE-2013-6800 krb5: KDC remote DoS (NULL pointer dereference and daemon crash)
1116180 - CVE-2014-4341 krb5: denial of service flaws when handling padding length longer than the plaintext
1121877 - CVE-2014-4344 krb5: NULL pointer dereference flaw in SPNEGO acceptor for continuation tokens
6. Package List:
Red Hat Enterprise Linux Desktop (v. 5 client):
Red Hat Enterprise Linux Desktop Workstation (v. 5 client):
Red Hat Enterprise Linux (v. 5 server):
These packages are GPG signed by Red Hat for security. Our key and
details on how to verify the signature are available from
The Red Hat security contact is <firstname.lastname@example.org>. More contact
details at https://access.redhat.com/security/team/contact/
Copyright 2014 Red Hat, Inc.
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