a server receives a TCP connection on a port that has been configured
for communication with a failover peer, this can cause it to become
non-responsive to all normal DHCP protocol traffic.
Posting date: 10 Dec 2010
If a TCP connection is established to the server
on a port which has been configured for communication with a failover
peer, this can cause it to become non-responsive to all normal DHCP
protocol traffic. The server will progress to a
communications-interrupted state - but in addition will also cease to
provide DHCP services to clients. The server must be restarted to
resume normal operation.
Impact and Risk Assessment:
This can be used as an attack vector against servers that are configured for failover partnerships
CVSS Score: 7.8
CVSS Equation: (AV:N/AC:L/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:N/AC:L/Au:N/C:N/I:N/A:C)
Users running DHCP servers in failover
configurations may be able to minimise the risk to TCP ports used for
peer-peer DHCP server communication by careful packet filtering on the
hosts and network gateways that limits access to traffic between the
configured failover peers - but ideally they should upgrade.
(Regardless of which version of DHCP is deployed, users are advised that
it is good security practice to limit traffic to their omapi and
failover ports via packet filters, firewalls etc.)
None known at this time. Issue found by a user and
reported via the dhcp-users community mailing list, therefore consider
this vulnerability public.
Upgrade DHCP to 4.2.0-P2.
Acknowledgements: Brad Bendily for finding and testing the problem.
If you'd like more information on our Forum or product support please visit 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.
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-00966 is the complete and official security advisory document.
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