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<pre wrap=""> ISC DHCP 3.1-ESV-R1, 4.1-ESV-R2 and 4.2.1-P1 are now available for download.
These are SECURITY releases of ISC DHCP, and fix one security
related bug. The security advisory is included below.
A list of the changes per release has been appended to the end
of this message. For a complete list of changes from any previous
release, please consult the RELNOTES file within the source
distribution, or on our website:
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://www.isc.org/software/dhcp">http://www.isc.org/software/dhcp</a>
The releases, and their OpenPGP-signatures are available now from:
DHCP 3.1-ESV-R1:
<a class="moz-txt-link-freetext" href="http://www.isc.org/software/dhcp/31-esv-r1">http://www.isc.org/software/dhcp/31-esv-r1</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-3.1-ESV-R1.tar.gz</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-3.1-ESV-R1.tar.gz</a>.<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz.sha512.asc">sha512.asc</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-3.1-ESV-R1.tar.gz</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz.sha256.asc">.sha256.asc</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-3.1-ESV-R1.tar</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz.sha1.asc">.gz.sha1.asc</a>
DHCP 4.1-ESV-R2:
<a class="moz-txt-link-freetext" href="http://www.isc.org/software/dhcp/41-esv-r2">http://www.isc.org/software/dhcp/41-esv-r2</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-4.1-ESV-R2.tar.gz</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-4.1-ESV-R2.tar.gz</a>.<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz.sha512.asc">sha512.asc</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-4.1-ESV-R2.tar.gz</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz.sha256.asc">.sha256.asc</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-4.1-ESV-R2.tar</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz.sha1.asc">.gz.sha1.asc</a>
DHCP 4.2.1-P1:
<a class="moz-txt-link-freetext" href="http://www.isc.org/software/dhcp/421-p1">http://www.isc.org/software/dhcp/421-p1</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.1-P1.tar.gz</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">4.2.1-P1</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">.tar.gz</a>.<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz.sha512.asc">sha512.asc</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">4.2.1-P1</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">.tar.gz</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz.sha256.asc">.sha256.asc</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">ftp://ftp.isc.org/isc/dhcp/dhcp-</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">4.2.1-P1</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz">.tar</a><a moz-do-not-send="true" class="moz-txt-link-freetext" href="ftp://ftp.isc.org/isc/dhcp/dhcp-4.2.0-P2.tar.gz.sha1.asc">.gz.sha1.asc</a>
ISC's Release Signing Key can be obtained at:
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://www.isc.org/about/openpgp/">http://www.isc.org/about/openpgp/</a>
Security Advisory:
</pre>
<pre>
Title: dhclient does not strip or escape shell meta-characters
Summary: dhclient doesn't strip or escape certain shell
meta-characters in
dhcpd responses, allowing a rogue server or party with with
escalated
privileges on the server to cause remote code execution on the
client.
</pre>
<pre>
CVE: CVE-2011-0997
CERT: VU# 107886
Posting date: 5 Apr 2011
Program Impacted: DHCP
Versions affected: 3.0.x-4.2.x
Severity: Medium
Exploitable: remotely
Description:
ISC dhclient did not strip or escape certain shell
meta-characters in
responses from the dhcp server (like hostname) before passing
the
responses on to dhclient-script. Depending on the script and OS,
this
can result in execution of exploit code on the client.
CVSS Score: 6.8 (AV:A/AC:L/Au:N/C:P/I:N/A:C)
For more information on CVSS scores, visit
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2">http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2</a>
Workarounds:
On SUSE systems, it is possible to disable hostname update by
setting
DHCLIENT_SET_HOSTNAME="no" in /etc/sysconfig/network/dhcp.
Other systems may add following line to dhclient-script at the
beginning
of the set_hostname() function:
new_host_name=${new_host_name//[^a-zA-Z0-9]/}
In environments where filters/acls can be put into place to
limit clients
to accessing only legitimate dhcp servers, this will protect
clients
from rogue dhcp servers deliberately trying to exploit this bug.
However,
this will not protect from compromised servers.
Active exploits:
None known at this time.
Solution:
</pre>
<pre>
Upgrade to 3.1-ESV-R1, 4.1-ESV-R2 or 4.2.1-P1.
</pre>
<pre>Acknowledgments: Sebastian Krahmer and Marius Tomaschewski, SUSE
Security Team
</pre>
<pre>
Questions regarding this advisory or ISC's Support services
should be
sent to <a moz-do-not-send="true" href="mailto:dhcp-bugs@isc.org">dhcp-bugs@isc.org</a>
</pre>
<pre wrap="">
Changes since 4.2.1
! In dhclient check the data for some string options for
reasonableness before passing it along to the script that
interfaces with the OS.
[ISC-Bugs #23722]
CVE: CVE-2011-0997
****************************
Changes since 4.1-ESV-R1
! In dhclient check the data for some string options for
reasonableness before passing it along to the script that
interfaces with the OS.
[ISC-Bugs #23722]
CVE: CVE-2011-0997
****************************
Changes since 3.1-ESV
- The 'domain-list' atom documentation in common/dhcp-options.5 was
corrected. [ISC-Bugs #21217]
! In dhclient check the data for some string options for
reasonableness before passing it along to the script that
interfaces with the OS.
[ISC-Bugs #23722]
CVE: CVE-2011-0997
</pre>
<pre>
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<pre class="moz-signature" cols="72">--
Larissa Shapiro
Internet Systems Consortium Product Manager
Technology Leadership for the Common Good
+1 650 423 1335
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="http://www.isc.org">www.isc.org</a></pre>
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