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CISC-RT-000050 - The Cisco router must be configured to enable routing protocol authentication using FIPS 198-1 algorithms with keys not exceeding 180 days of lifetime.

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Information

A rogue router could send a fictitious routing update to convince a site's perimeter router to send traffic to an incorrect or even a rogue destination. This diverted traffic could be analyzed to learn confidential information about the site's network or used to disrupt the network's ability to communicate with other networks. This is known as a "traffic attraction attack" and is prevented by configuring neighbor router authentication using FIPS 198-1 algorithms for routing updates.
If the keys used for 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 is 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. If a time period occurs during which no key is activated, neighbor authentication cannot occur, and therefore routing updates will fail.

Solution

Configure routing protocol authentication to use a NIST-validated FIPS 198-1 message authentication code algorithm with keys not exceeding 180 days of lifetime as shown in the examples.

BGP Example:

Step 1: Configure a keychain using a FIPS 198-1 algorithm with a key duration not exceeding 180 days.

key chain <KEY-CHAIN-NAME> tcp
key <KEY-ID>
send-id <ID>
recv-id <ID>
cryptographic-algorithm hmac-sha256
key-string <KEY>
accept-lifetime 00:00:00 Jan 1 2022 duration 180
send-lifetime 00:00:00 Jan 1 2022 duration 180
!

Step 2: Configure BGP autonomous system to use the keychain for authentication.

router bgp <ASN>
no synchronization
bgp log-neighbor-changes
neighbor x.x.x.x remote-as <ASN>
neighbor x.x.x.x ao <KEY-CHAIN-NAME>

OSPF Example:

Step 1: Configure a keychain using a FIPS 198-1 algorithm with a key duration not exceeding 180 days.

key chain OSPF_KEY_CHAIN
key 1
key-string xxxxxxx
send-lifetime 00:00:00 Jan 1 2018 23:59:59 Mar 31 2018
accept-lifetime 00:00:00 Jan 1 2018 01:05:00 Apr 1 2018
cryptographic-algorithm hmac-sha-256
key 2
key-string yyyyyyy
send-lifetime 00:00:00 Apr 1 2018 23:59:59 Jun 30 2018
accept-lifetime 23:55:00 Mar 31 2018 01:05:00 Jul 1 2018
cryptographic-algorithm hmac-sha-256

Step 2: Configure OSPF to use the keychain for authentication.

interface GigabitEthernet0/1
ip address x.x.x.x 255.255.255.0
ip ospf authentication key-chain OSPF_KEY_CHAIN

See Also

https://s3.us-gov-west-1.amazonaws.com/dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_IOS-XE_Router_Y25M07_STIG.zip

Item Details

References: CAT|II, CCI|CCI-000803, CCI|CCI-002205, Rule-ID|SV-216645r1007829_rule, STIG-ID|CISC-RT-000050, STIG-Legacy|SV-106001, STIG-Legacy|V-96863, Vuln-ID|V-216645

Plugin: Cisco

Control ID: 834fd3a3857002848158c6a58915a45bcb1b96ef3a166834c8a8bab5b49844d3