The Cisco switch must uniquely identify all network-connected endpoint devices before establishing any connection.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-220675	CISC-L2-000020	SV-220675r539671_rule		High

Description
Controlling LAN access via 802.1x authentication can assist in preventing a malicious user from connecting an unauthorized PC to a switch port to inject or receive data from the network without detection.

STIG	Date
Cisco NX OS Switch L2S Security Technical Implementation Guide	2023-06-01

Details

Check Text ( C-22390r539076_chk )
Verify if the switch configuration has 802.1x authentication implemented for all access switch ports connecting to LAN outlets (i.e., RJ-45 wall plates) or devices not located in the telecom room, wiring closets, or equipment rooms. MAC Authentication Bypass (MAB) must be configured on those switch ports connected to devices that do not support an 802.1x supplicant. Step 1: Verify that 802.1x is configured on all host-facing interfaces as shown in the example below: interface Ethernet1/1 dot1x pae authenticator dot1x port-control auto dot1x host-mode single-host switchport access vlan 10 interface Ethernet1/2 dot1x pae authenticator dot1x port-control auto dot1x host-mode single-host switchport access vlan 10 interface Ethernet1/3 dot1x pae authenticator dot1x port-control auto dot1x host-mode single-host switchport access vlan 10 Note: Host-mode must be set to single-host, multi-domain (for VoIP phone + PC), or multi-auth (multiple PCs connected to a hub). Host-mode multi-host is not compliant with this requirement. Step 2: Verify that 802.1x authentication is configured on the switch as shown in the example below: aaa group server radius RADIUS_GROUP server 1.1.1.1 server 1.2.1.1 … … … aaa authentication dot1x default group RADIUS_GROUP Step 3: Verify that the radius servers have been defined. radius-server host 10.1.1.1 key 7 "xxxxxxxxxxx" authentication accounting timeout 5 retransmit 1 radius-server host 10.2.1.1 key 7 " xxxxxxxxxxx" authentication accounting timeout 5 retransmit 1 If 802.1x authentication or MAB is not configured on all access switch ports connecting to LAN outlets or devices not located in the telecom room, wiring closets, or equipment rooms, this is a finding.

Check Text ( C-22390r539076_chk )

Verify if the switch configuration has 802.1x authentication implemented for all access switch ports connecting to LAN outlets (i.e., RJ-45 wall plates) or devices not located in the telecom room, wiring closets, or equipment rooms. MAC Authentication Bypass (MAB) must be configured on those switch ports connected to devices that do not support an 802.1x supplicant.

Step 1: Verify that 802.1x is configured on all host-facing interfaces as shown in the example below:

interface Ethernet1/1
dot1x pae authenticator
dot1x port-control auto
dot1x host-mode single-host
switchport access vlan 10

interface Ethernet1/2
dot1x pae authenticator
dot1x port-control auto
dot1x host-mode single-host
switchport access vlan 10

interface Ethernet1/3
dot1x pae authenticator
dot1x port-control auto
dot1x host-mode single-host
switchport access vlan 10

Note: Host-mode must be set to single-host, multi-domain (for VoIP phone + PC), or multi-auth (multiple PCs connected to a hub). Host-mode multi-host is not compliant with this requirement.

Step 2: Verify that 802.1x authentication is configured on the switch as shown in the example below:

aaa group server radius RADIUS_GROUP
server 1.1.1.1
server 1.2.1.1
…
…
…
aaa authentication dot1x default group RADIUS_GROUP

Step 3: Verify that the radius servers have been defined.

radius-server host 10.1.1.1 key 7 "xxxxxxxxxxx" authentication accounting timeout 5 retransmit 1
radius-server host 10.2.1.1 key 7 " xxxxxxxxxxx" authentication accounting timeout 5 retransmit 1

If 802.1x authentication or MAB is not configured on all access switch ports connecting to LAN outlets or devices not located in the telecom room, wiring closets, or equipment rooms, this is a finding.

Fix Text (F-22379r539077_fix)
Configure 802.1 x authentications on all host-facing access switch ports. To authenticate those devices that do not support 802.1x, MAC Authentication Bypass must be configured. Step 1: Configure the radius servers as shown in the example below: SW1(config)# radius-server host 10.1.1.1 key xxxx SW1(config)# radius-server host 10.2.1.1 key xxxx Step 2: Enable 802.1x authentication on the switch. SW1(config)# aaa group server radius RADIUS_GROUP SW1(config-radius)# server 10.1.1.1 SW1(config-radius)# server 10.2.1.1 SW1(config-radius)# exit SW1(config)# aaa authentication dot1x default group RADIUS_GROUP SW1(config)# exit Step 3: Enable 802.1x on all host-facing interfaces as shown in the example below: SW1(config)# int e1/1 - 80 SW1(config-if-range)# dot1x port-control auto SW1(config-if-range)# dot1x host-mode single-host SW1(config-if-range)# end Note: Host-mode must be set to single-host, multi-domain (for VoIP phone + PC), or multi-auth (multiple PCs connected to a hub). Host-mode multi-host is not compliant with this requirement.

Fix Text (F-22379r539077_fix)

Configure 802.1 x authentications on all host-facing access switch ports. To authenticate those devices that do not support 802.1x, MAC Authentication Bypass must be configured.

Step 1: Configure the radius servers as shown in the example below:

SW1(config)# radius-server host 10.1.1.1 key xxxx
SW1(config)# radius-server host 10.2.1.1 key xxxx

Step 2: Enable 802.1x authentication on the switch.

SW1(config)# aaa group server radius RADIUS_GROUP
SW1(config-radius)# server 10.1.1.1
SW1(config-radius)# server 10.2.1.1
SW1(config-radius)# exit
SW1(config)# aaa authentication dot1x default group RADIUS_GROUP
SW1(config)# exit

Step 3: Enable 802.1x on all host-facing interfaces as shown in the example below:

SW1(config)# int e1/1 - 80
SW1(config-if-range)# dot1x port-control auto
SW1(config-if-range)# dot1x host-mode single-host
SW1(config-if-range)# end

Note: Host-mode must be set to single-host, multi-domain (for VoIP phone + PC), or multi-auth (multiple PCs connected to a hub). Host-mode multi-host is not compliant with this requirement.