The Cisco ISR 4000 Series router Series must be configured so that any key used for authenticating Interior Gateway Protocol peers does not have a duration exceeding 180 days.

From Cisco IOS XE Release 3 RTR Security Technical Implementation Guide

Part of SRG-NET-000025-RTR-000085

Associated with: CCI-000366 CCI-002205

SV-88795r1_rule The Cisco ISR 4000 Series router Series must be configured so that any key used for authenticating Interior Gateway Protocol peers does not have a duration exceeding 180 days.

Vulnerability discussion

If the keys used for routing protocol authentication are guessed, the malicious user could create havoc within the network by advertising incorrect routes and redirecting traffic. Some routing protocols allow the use of key chains for authentication. A key chain is a set of keys that are used in succession, with each having a lifetime of no more than 180 days. Changing the keys frequently reduces the risk of them eventually being guessed.Keys cannot be used during time periods for which they are not activated. If a time period occurs during which no key is activated, neighbor authentication cannot occur, and therefore routing updates will fail. Therefore, you should ensure that for a given key chain, key activation times overlap to avoid any period of time during which no key is activated.

Check content

Review the Cisco ISR 4000 Series router configuration to verify that all IGPs deployed on the router utilizing a key chain do not have a key with a duration exceeding “180” days. The configuration should look similar to the example below: interface Ethernet 0 ip authentication mode eigrp 1 md5 ip authentication key-chain eigrp 1 KEY_CHAIN ... router eigrp 1 network x.x.x.x ... key chain KEY_CHAIN key 1 key-string willow accept-lifetime 22:45:00 Feb 10 2016 22:45:00 Aug 10 2016 send-lifetime 23:00:00 Feb 10 2016 22:45:00 Aug 10 2016 key 2 key-string birch accept-lifetime 22:45:00 Aug 9 2016 22:45:00 Feb 10 2006 send-lifetime 23:00:00 Aug 9 2016 22:45:00 Feb 10 2006 key 3 key-string maple accept-lifetime 22:45:00 Feb 10 2006 22:45:00 Aug 10 2006 send-lifetime 23:00:00 Feb 10 2006 22:45:00 Aug 10 2006 If the Cisco ISR 4000 Series router is configured with a key chain with a duration exceeding “180” days, this is a finding.

Fix text

Configure all key chain used for IGP authentication to have keys that will not have a duration exceeding “180” days as shown in the example below: key chain KEY_CHAIN key 1 key-string willow accept-lifetime 22:45:00 Feb 10 2016 22:45:00 Aug 10 2016 send-lifetime 23:00:00 Feb 10 2016 22:45:00 Aug 10 2016 key 2 key-string birch accept-lifetime 22:45:00 Aug 9 2016 22:45:00 Feb 10 2006 send-lifetime 23:00:00 Aug 9 2016 22:45:00 Feb 10 2006 key 3 key-string maple accept-lifetime 22:45:00 Feb 10 2006 22:45:00 Aug 10 2006 send-lifetime 23:00:00 Feb 10 2006 22:45:00 Aug 10 2006

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