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

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-216644	CISC-RT-000040	SV-216644r531086_rule		Medium

Description
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 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.

Description

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 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.

STIG	Date
Cisco IOS XE Router RTR Security Technical Implementation Guide	2021-03-26

Details

Check Text ( C-17877r287892_chk )
Review the router configuration. For every routing protocol that affects the routing or forwarding tables, verify that neighbor router authentication is encrypting the authentication key as shown in the examples below. BGP Example: router bgp nn no synchronization bgp log-neighbor-changes neighbor x.x.x.x remote-as nn neighbor x.x.x.x password xxxxxxx Note: BGP authentication uses MD5 EIGRP Example: interface GigabitEthernet1/0 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 IS-IS Example: interface GigabitEthernet1/0 ip address x.x.x.x 255.255.255.0 ip router isis isis authentication mode md5 isis authentication key-chain ISIS_KEY_CHAIN OSPF Example: interface GigabitEthernet1/0 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 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.

Check Text ( C-17877r287892_chk )

Review the router configuration. For every routing protocol that affects the routing or forwarding tables, verify that neighbor router authentication is encrypting the authentication key as shown in the examples below.

BGP Example:

router bgp nn
no synchronization
bgp log-neighbor-changes
neighbor x.x.x.x remote-as nn
neighbor x.x.x.x password xxxxxxx

Note: BGP authentication uses MD5

EIGRP Example:

interface GigabitEthernet1/0
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

IS-IS Example:

interface GigabitEthernet1/0
ip address x.x.x.x 255.255.255.0
ip router isis
isis authentication mode md5
isis authentication key-chain ISIS_KEY_CHAIN

OSPF Example:

interface GigabitEthernet1/0
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
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.

Fix Text (F-17875r287893_fix)
Configure all routing protocol authentications to encrypt the authentication key. BGP Example: R1(config)#router bgp nn R1(config-router)#neighbor x.x.x.x password xxxxxx EIGRP Example: R2(config)#int g0/1 R2(config-if)#ip authentication mode eigrp 1 md5 R2(config-if)#ip authentication key-chain eigrp 1 EIGRP_KEY_CHAIN IS-IS Example: R5(config)#int g0/1 R5(config-if)#isis authentication mode md5 R5(config-if)#isis authentication key-chain ISIS_KEY_CHAIN OSPF Example: R1(config)#int g1/0 R1(config-if)#ip ospf authentication message-digest R1(config-if)#ip ospf message-digest-key 1 md5 xxxxxx RIP Example: R2(config)#int g1/0 R2(config-if)#ip rip authentication mode md5 R2(config-if)#ip rip authentication key-chain RIP_KEY_CHAIN

Fix Text (F-17875r287893_fix)

Configure all routing protocol authentications to encrypt the authentication key.

BGP Example:

R1(config)#router bgp nn
R1(config-router)#neighbor x.x.x.x password xxxxxx

EIGRP Example:

R2(config)#int g0/1
R2(config-if)#ip authentication mode eigrp 1 md5
R2(config-if)#ip authentication key-chain eigrp 1 EIGRP_KEY_CHAIN

IS-IS Example:

R5(config)#int g0/1
R5(config-if)#isis authentication mode md5
R5(config-if)#isis authentication key-chain ISIS_KEY_CHAIN

OSPF Example:

R1(config)#int g1/0
R1(config-if)#ip ospf authentication message-digest
R1(config-if)#ip ospf message-digest-key 1 md5 xxxxxx

RIP Example:

R2(config)#int g1/0
R2(config-if)#ip rip authentication mode md5
R2(config-if)#ip rip authentication key-chain RIP_KEY_CHAIN