Bug 157103 - CAN-2005-1174 krb5 buffer overflow, heap corruption in KDC (CAN-2005-1175)
CAN-2005-1174 krb5 buffer overflow, heap corruption in KDC (CAN-2005-1175)
Status: CLOSED ERRATA
Product: Red Hat Enterprise Linux 4
Classification: Red Hat
Component: krb5 (Show other bugs)
4.0
All Linux
medium Severity high
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Assigned To: Nalin Dahyabhai
Brian Brock
impact=important,public=20050612,sour...
: Security
Depends On:
Blocks:
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Reported: 2005-05-06 16:56 EDT by Josh Bressers
Modified: 2007-11-30 17:07 EST (History)
1 user (show)

See Also:
Fixed In Version: RHSA-2005-567
Doc Type: Bug Fix
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Last Closed: 2005-07-12 14:15:49 EDT
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RHEL 7.3 requirements from Atomic Host:


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Description Josh Bressers 2005-05-06 16:56:31 EDT
The MIT krb5 Key Distribution Center (KDC) implementation can corrupt
the heap by attempting to free memory at a random address when it
receives a certain unlikely (but valid) request via a TCP connection.
This attempt to free unallocated memory can result in a KDC crash and
consequent denial of service.  [CAN-2005-1174]

Additionally, the same request, when received by the KDC via either
TCP or UDP, can trigger a bug in the krb5 library which results in a
single-byte overflow of a heap buffer.  Additionally, application
servers are vulnerable to a highly improbable attack, provided that
the attacker controls a realm sharing a cross-realm key with the
target realm. [CAN-2005-1175]

An unauthenticated attacker may be able to use these vulnerabilities
to execute arbitrary code on the KDC host, potentially compromising an
entire Kerberos realm.  No exploit code is known to exist at this
time.  Exploitation of these vulnerabilities is believed to be
difficult.
Comment 1 Josh Bressers 2005-05-06 17:00:26 EDT
Nalin,

It seems CAN-2005-1174 sin't going to affect RHEL2.1 or RHEL3, can you verify this?

CAN-2005-1175 should affect RHEL2.1, RHEL3, and RHEL4
Comment 2 Nalin Dahyabhai 2005-06-30 02:08:04 EDT
I can confirm that CAN-2005-1174 shouldn't affect RHEL 2.1 or 3.  Both releases
include krb5 1.2.x, which predates the TCP code.  (The variable in question is
there, but the code path which leads to it being mistakenly passed to free()
before it's initialized isn't.)
Comment 3 Josh Bressers 2005-07-07 08:59:41 EDT
According to MIT, in order to exploit CAN-2005-1175 the attacker must control a
realm sharing a cross-realm key with the target realm.  I'm lowering the
severity to "moderate" for that particular issue.
Comment 4 Mark J. Cox (Product Security) 2005-07-12 13:59:35 EDT
public, removing embargo
http://web.mit.edu/kerberos/www/advisories/
Comment 5 Red Hat Bugzilla 2005-07-12 14:15:49 EDT
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2005-567.html

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