copyright | disclaimer | privacy | contact  
Australia's Leading Computer Emergency Response Team
 
Search this site

 
On this site

 > HOME
 > About AusCERT
 > Membership
 > Contact Us
 > PKI Services
 > Publications
 > Sec. Bulletins
 > Conferences
 > News & Media
 > Services
 > Web Log
 > Site Map
 > Site Help
 > Member login





 

ESB-2012.0882 - [Win][UNIX/Linux] DHCP: Denial of service - Remote/unauthenticated

Date: 14 September 2012
References: ESB-2012.0910  ESB-2013.0248  ESB-2013.0306  

Click here for printable version
Click here for PGP verifiable version
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

===========================================================================
             AUSCERT External Security Bulletin Redistribution

                               ESB-2012.0882
          CVE-2012-3955: Reducing the expiration time for an IPv6
                    lease may cause the server to crash
                             14 September 2012

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

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           DHCP
Publisher:         Internet Systems Consortium
Operating System:  Windows
                   UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2012-3955  

Original Bulletin: 
   https://kb.isc.org/article/AA-00779/75

- --------------------------BEGIN INCLUDED TEXT--------------------

CVE-2012-3955: Reducing the expiration time for an IPv6 lease may cause the 
server to crash

Author: Cathy Almond 
Reference Number: AA-00779 
Created: 2012-08-23 15:08 
Last Updated: 2012-09-12 16:26	

CVE: CVE-2012-3955
Document Version: 2.0
Posting date: 12 September 2012
Program Impacted: ISC DHCP 4
Versions affected: 4.1.x, 4.2.x
Severity: Medium
Exploitable: From networks permitted to send requests to the DHCP server.

Description:

ISC has discovered that reducing the expiration time for an active IPv6 lease 
may cause the server to crash.

Please Note: Versions of ISC DHCP 4.0 may also be affected, but these branches 
are beyond their "end of life" (EOL) and no longer receive testing or security 
fixes from ISC. For current information on which versions are actively 
supported, please see http://www.isc.org/software/dhcp/versions.

Impact:

Affected servers can terminate unexpectedly, resulting in a denial of service 
condition for clients.

CVSS Score:  5.7

CVSS Equation:  (AV:A/AC:M/Au:N/C:N/I:N/A:C)

For more information on the Common Vulnerability Scoring System and to obtain 
your specific environmental score please visit: 
http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2&vector=(AV:A/AC:M/Au:N/C:N/I:N/A:C)

Workarounds:

ISC recommends setting a value for the default-lease-time option in the 
configuration file, and not reducing it once set.

Active exploits:

No known active exploits.

Solution:  Upgrade to the updated release most closely related to your current 
version of DHCP.  These can be downloaded from 
http://www.isc.org/downloads/all.

    ISC DHCP version 4.1-ESV-R7
    ISC DHCP version 4.2.4-P2

Acknowledgements: ISC would like to thank Glen Eustace of Massey University, 
New Zealand for finding this issue.

Document Revision History:

1.0 - 4 Sept. 2012 Advance Notification to Phase 1
1.1 - 11 Sept. 2012 Phase 2 & 3 notified
2.0 - 12 Sept. 2012 Phase 4 - Public Released

Related Documents:

If you'd like more information on our Forum or product support please visit 
www.isc.org/software/guild or www.isc.org/support.

Do you still have questions?  Questions regarding this advisory should go to 
security-officer@isc.org

Note: ISC patches only currently supported versions. When possible we indicate 
EOL versions affected.

ISC Security Vulnerability Disclosure Policy:  Details of our current security 
advisory policy and practice can be found here: 
https://www.isc.org/security-vulnerability-disclosure-policy

This Knowledge Base article https://kb.isc.org/article/AA-00779 is the complete 
and official security advisory document.  There is also a summary article 
located on our website and linking to here: 
https://www.isc.org/software/bind/advisories/cve-2012-3955.

Legal Disclaimer:
Internet Systems Consortium (ISC) is providing this notice on an "AS IS" basis. 
No warranty or guarantee of any kind is expressed in this notice and none 
should be implied. ISC expressly excludes and disclaims any warranties 
regarding this notice or materials referred to in this notice, including, 
without limitation, any implied warranty of merchantability, fitness for a 
particular purpose, absence of hidden defects, or of non-infringement. Your use 
or reliance on this notice or materials referred to in this notice is at your 
own risk. ISC may change this notice at any time.  A stand-alone copy or 
paraphrase of the text of this document that omits the document URL is an 
uncontrolled copy. Uncontrolled copies may lack important information, be out 
of date, or contain factual errors.

(c) 2001-2012 Internet Systems Consortium

- --------------------------END INCLUDED TEXT--------------------

You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to auscert@auscert.org.au
and we will forward your request to the appropriate person.

NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.

NOTE: This is only the original release of the security bulletin.  It may
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

        http://www.auscert.org.au/render.html?cid=1980

===========================================================================
Australian Computer Emergency Response Team
The University of Queensland
Brisbane
Qld 4072

Internet Email: auscert@auscert.org.au
Facsimile:      (07) 3365 7031
Telephone:      (07) 3365 4417 (International: +61 7 3365 4417)
                AusCERT personnel answer during Queensland business hours
                which are GMT+10:00 (AEST).
                On call after hours for member emergencies only.
===========================================================================
-----BEGIN PGP SIGNATURE-----
Comment: http://www.auscert.org.au/render.html?it=1967
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=bVFt
-----END PGP SIGNATURE-----