CVE-2010-3616: DHCP: Server Hangs with TCP to Failover Peer Port
If 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.
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.
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Note: ISC patches only currently supported versions.
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This Knowledge Base article https://kb.isc.org/article/AA-00966 is the complete and official security advisory document.
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