Bug 157103

Summary: CAN-2005-1174 krb5 buffer overflow, heap corruption in KDC (CAN-2005-1175)
Product: Red Hat Enterprise Linux 4 Reporter: Josh Bressers <bressers>
Component: krb5Assignee: Nalin Dahyabhai <nalin>
Status: CLOSED ERRATA QA Contact: Brian Brock <bbrock>
Severity: high Docs Contact:
Priority: medium    
Version: 4.0CC: security-response-team
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard: impact=important,public=20050612,source=mit,reported=20050426
Fixed In Version: RHSA-2005-567 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2005-07-12 18:15:49 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Josh Bressers 2005-05-06 20:56:31 UTC 
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 21:00:26 UTC 
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 06:08:04 UTC 
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 12:59:41 UTC 
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 2005-07-12 17:59:35 UTC 
public, removing embargo
http://web.mit.edu/kerberos/www/advisories/
Comment 5 Red Hat Bugzilla 2005-07-12 18:15:49 UTC 
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