[UNIX] Multiple Vendor Kerberos kadmind Buffer Overflow Vulnerability

The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com
- - promotion

The SecuriTeam alerts list - Free, Accurate, Independent.

Get your security news from a reliable source.
http://www.securiteam.com/mailinglist.html

- - - - - - - - -



Multiple Vendor Kerberos kadmind Buffer Overflow Vulnerability
------------------------------------------------------------------------


SUMMARY

<http://web.mit.edu/Kerberos/> Kerberos is "a network authentication
protocol. It is used in client-server systems to provide user
authentication by using a ticket based system. kadmind is the Kerberos
administration server. It is used to configure principals and policies on
the Kerberos".

Remote exploitation of a buffer overflow vulnerability in the Kerberos
kadmind server, as included in various vendors' operating system
distributions, could allow attackers to execute arbitrary code on a
targeted host.

DETAILS

Vulnerable Systems:
* Kerberos version 1.5.1 on Fedora CORE 5

Immune Systems:
* Kerberos version 1.6.1

The vulnerability exists within the server's logging function,
klog_vsyslog(). A call is made to vsprintf(), with the destination buffer
passed as a fixed size stack buffer. User input is not properly validated
before being passed to this function, and a stack based buffer overflow
can occur.

Analysis:
Exploitation allows an attacker to execute arbitrary code with root
privileges on the targeted host.

In order to exploit this vulnerability, an attacker must have valid
credentials stored on the server. Administrator privileges are not
necessary. The kadmind server runs on the master Kerberos server. Since
the master server holds the KDC principal and policy database, a
compromise could lead to a compromise of multiple hosts that use the
server for authentication.

Workaround:
iDefense is currently unaware of any workarounds for this issue.

Vendor response:
The MIT Kerberos team has made patches available to address this
vulnerability. For more information consult their advisory at the
following URL:
<http://web.mit.edu/Kerberos/advisories/MITKRB5-SA-2007-002-syslog.txt>
http://web.mit.edu/Kerberos/advisories/MITKRB5-SA-2007-002-syslog.txt

CVE Information:
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-0957>
CVE-2007-0957

Disclosure Timeline:
02/08/2007 - Initial vendor notification
02/08/2007 - Initial vendor response
04/03/2007 - Coordinated public disclosure


ADDITIONAL INFORMATION

The information has been provided by iDefense Labs.
The original article can be found at:
<http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=500>
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=500



========================================


This bulletin is sent to members of the SecuriTeam mailing list.
To unsubscribe from the list, send mail with an empty subject line and body to: list-unsubscribe@xxxxxxxxxxxxxx
In order to subscribe to the mailing list, simply forward this email to: list-subscribe@xxxxxxxxxxxxxx


====================
====================

DISCLAIMER:
The information in this bulletin is provided "AS IS" without warranty of any kind.
In no event shall we be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages.

Relevant Pages