The Cisco switch must be configured to authenticate all routing protocol messages using NIST-validated FIPS 198-1 message authentication code algorithm.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-221075	CISC-RT-000050	SV-221075r622190_rule		Medium

Description
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. Since MD5 is vulnerable to "birthday" attacks and may be compromised, routing protocol authentication must use FIPS 140-2 validated algorithms and modules to encrypt the authentication key. 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 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. Since MD5 is vulnerable to "birthday" attacks and may be compromised, routing protocol authentication must use FIPS 140-2 validated algorithms and modules to encrypt the authentication key. 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 NX-OS Switch RTR Security Technical Implementation Guide	2021-03-29

Details

Check Text ( C-22790r409714_chk )
Review the switch configuration to verify it is using a NIST-validated FIPS 198-1 message authentication code algorithm to authenticate routing protocol messages. OSPF Example key chain OSPF_KEY key 1 key-string 7 070d2e4e4c10 accept-lifetime 00:00:00 Oct 01 2019 01:05:00 Jan 01 2020 send-lifetime 00:00:00 Oct 01 2019 23:59:59 Dec 31 2019 cryptographic-algorithm hmac-sha-256 key 2 key-string 7 0704205e4b07 accept-lifetime 23:55:00 Dec 31 2019 01:05:00 Apr 01 2020 send-lifetime 00:00:00 Jan 01 2020 23:59:59 Mar 31 2020 cryptographic-algorithm hmac-sha-256 … … … interface Ethernet2/2 no switchport ip ospf authentication key-chain OSPF_KEY Note: BGP, RIP, EIGRP, IS-IS do not support any FIPS 198-1 HMAC algorithms. If a NIST-validated FIPS 198-1 message authentication code algorithm is not being used to authenticate routing protocol messages, this is a finding.

Check Text ( C-22790r409714_chk )

Review the switch configuration to verify it is using a NIST-validated FIPS 198-1 message authentication code algorithm to authenticate routing protocol messages.

OSPF Example

key chain OSPF_KEY
key 1
key-string 7 070d2e4e4c10
accept-lifetime 00:00:00 Oct 01 2019 01:05:00 Jan 01 2020
send-lifetime 00:00:00 Oct 01 2019 23:59:59 Dec 31 2019
cryptographic-algorithm hmac-sha-256
key 2
key-string 7 0704205e4b07
accept-lifetime 23:55:00 Dec 31 2019 01:05:00 Apr 01 2020
send-lifetime 00:00:00 Jan 01 2020 23:59:59 Mar 31 2020
cryptographic-algorithm hmac-sha-256
…
…
…
interface Ethernet2/2
no switchport
ip ospf authentication key-chain OSPF_KEY

Note: BGP, RIP, EIGRP, IS-IS do not support any FIPS 198-1 HMAC algorithms.

If a NIST-validated FIPS 198-1 message authentication code algorithm is not being used to authenticate routing protocol messages, this is a finding.

Fix Text (F-22779r409715_fix)
Configure routing protocol authentication to use a NIST-validated FIPS 198-1 message authentication code algorithm as shown in the example below: SW1(config)# key chain OSPF_KEY SW1(config-keychain)# key 1 SW1(config-keychain-key)# key-string xxxxxxxxxxxx SW1(config-keychain-key)# send-lifetime 00:00:00 Oct 1 2019 23:59:59 Dec 31 2019 SW1(config-keychain-key)# accept-lifetime 00:00:00 Oct 1 2019 01:05:00 Jan 1 2020 SW1(config-keychain-key)# cryptographic-algorithm hmac-sha-256 SW1(config-keychain-key)# key 2 SW1(config-keychain-key)# key-string kxxxxxxxxxxxxx SW1(config-keychain-key)# send-lifetime 00:00:00 Jan 1 2020 23:59:59 Mar 31 2020 SW1(config-keychain-key)# accept-lifetime 23:55:00 Dec 31 2019 01:05:00 Apr 1 2020 SW1(config-keychain-key)# cryptographic-algorithm hmac-sha-256 SW1(config-keychain-key)# end SW1(config)# int e2/2 SW2(config-if)# ip ospf authentication key-chain OSPF_KEY

Fix Text (F-22779r409715_fix)

Configure routing protocol authentication to use a NIST-validated FIPS 198-1 message authentication code algorithm as shown in the example below:

SW1(config)# key chain OSPF_KEY
SW1(config-keychain)# key 1
SW1(config-keychain-key)# key-string xxxxxxxxxxxx
SW1(config-keychain-key)# send-lifetime 00:00:00 Oct 1 2019 23:59:59 Dec 31 2019
SW1(config-keychain-key)# accept-lifetime 00:00:00 Oct 1 2019 01:05:00 Jan 1 2020
SW1(config-keychain-key)# cryptographic-algorithm hmac-sha-256
SW1(config-keychain-key)# key 2
SW1(config-keychain-key)# key-string kxxxxxxxxxxxxx
SW1(config-keychain-key)# send-lifetime 00:00:00 Jan 1 2020 23:59:59 Mar 31 2020
SW1(config-keychain-key)# accept-lifetime 23:55:00 Dec 31 2019 01:05:00 Apr 1 2020
SW1(config-keychain-key)# cryptographic-algorithm hmac-sha-256
SW1(config-keychain-key)# end
SW1(config)# int e2/2
SW2(config-if)# ip ospf authentication key-chain OSPF_KEY