CVE-2012-3955: Reducing the expiration time for an IPv6 lease may cause the server to crash
12 September 2012
From networks permitted to send requests to the DHCP server.
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.
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)
ISC recommends setting a value for the default-lease-time option in the configuration file, and not reducing it once set.
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
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 email@example.com
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.
© 2001-2018 Internet Systems Consortium For assistance with problems and questions for which you have not been able to find an answer in our Knowledge Base, we recommend searching our community mailing list archives and/or posting your question there (you will need to register there first for your posts to be accepted). The bind-users and the dhcp-users lists particularly have a long-standing and active membership. ISC relies on the financial support of the community to fund the development of its open source software products. If you would like to support future product evolution and maintenance as well having peace of mind knowing that our team of experts are poised to provide you with individual technical assistance whenever you call upon them, then please consider our Professional Subscription Support services - details can be found on our main website.