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V-101587

The Cisco switch must be configured to use encryption for routing protocol authentication.

Finding ID
CISC-RT-000040
Rule ID
SV-110691r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-NET-000168-RTR-000077
CCI
CCI-000803
Target Key
(None)
Documentable
No
Discussion

A rogue switch could send a fictitious routing update to convince a site's perimeter switch 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 switch authentication for routing updates. However, using clear-text authentication provides little benefit since an attacker can intercept traffic and view the authentication key. This would allow the attacker to use the authentication key in an attack. This requirement applies to all IPv4 and IPv6 protocols that are used to exchange routing or packet forwarding information; this includes all Interior Gateway Protocols (such as OSPF, EIGRP, and IS-IS) and Exterior Gateway Protocols (such as BGP), MPLS-related protocols (such as LDP), and multicast-related protocols.

Fix Text

Configure all routing protocol authentications to encrypt the authentication key. EIGRP example: SW2(config)#int g0/1 SW2(config-if)#ip authentication mode eigrp 1 md5 SW2(config-if)#ip authentication key-chain eigrp 1 EIGRP_KEY_CHAIN OSPF example: SW1(config)#int g1/0 SW1(config-if)#ip ospf authentication message-digest SW1(config-if)#ip ospf message-digest-key 1 md5 xxxxxx RIP example: SW2(config)#int g1/0 SW2(config-if)#ip rip authentication mode md5 SW2(config-if)#ip rip authentication key-chain RIP_KEY_CHAIN

Check Content

Review the switch configuration. For every routing protocol that affects the routing or forwarding tables, verify that the switch is encrypting the authentication key as shown in the examples below: EIGRP example: interface GigabitEthernet1/0 no switchport ip address x.x.x.x 255.255.255.0 ip authentication mode eigrp 1 md5 ip authentication key-chain eigrp 1 EIGRP_KEY_CHAIN OSPF example: interface GigabitEthernet1/0 no switchport ip address x.x.x.x 255.255.255.0 ip ospf authentication message-digest ip ospf message-digest-key 1 md5 xxxxxx RIP example: interface GigabitEthernet1/0 no switchport ip rip authentication mode md5 ip rip authentication key-chain RIP_KEY_CHAIN If the routing protocol is not encrypting the authentication key, this is a finding.