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-101113	CISC-L2-000020	SV-110217r1_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 IOS Switch L2S Security Technical Implementation Guide	2020-05-07

Details

Check Text ( C-99993r1_chk )
Verify that 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 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 GigabitEthernet1/0 switchport access vlan 12 switchport mode access authentication port-control auto dot1x pae authenticator ! interface GigabitEthernet1/1 switchport access vlan 13 switchport mode access authentication port-control auto dot1x pae authenticator ! interface GigabitEthernet1/2 switchport access vlan 13 switchport mode access authentication port-control auto dot1x pae authenticator Step 2: Verify that 802.1x authentication is configured on the switch as shown in the example below: aaa new-model ! ! aaa group server radius RADIUS_SERVERS server name RADIUS_1 server name RADIUS_2 ! aaa authentication dot1x default group RADIUS_SERVERS … … … dot1x system-auth-control Step 3: Verify that the radius servers have been defined: SW1#show radius server-group RADIUS_SERVERS Note: Single-host is the default. Host-mode multi-domain (for VoIP phone plus PC) or multi-auth (multiple PCs connected to a hub) can be configured as alternatives. Host-mode multi-host is not compliant with this requirement. 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-99993r1_chk )

Verify that 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 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 GigabitEthernet1/0
switchport access vlan 12
switchport mode access
authentication port-control auto
dot1x pae authenticator
!
interface GigabitEthernet1/1
switchport access vlan 13
switchport mode access
authentication port-control auto
dot1x pae authenticator
!
interface GigabitEthernet1/2
switchport access vlan 13
switchport mode access
authentication port-control auto
dot1x pae authenticator

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

aaa new-model
!
!
aaa group server radius RADIUS_SERVERS
server name RADIUS_1
server name RADIUS_2
!
aaa authentication dot1x default group RADIUS_SERVERS
…
…
…
dot1x system-auth-control

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

SW1#show radius server-group RADIUS_SERVERS

Note: Single-host is the default. Host-mode multi-domain (for VoIP phone plus PC) or multi-auth (multiple PCs connected to a hub) can be configured as alternatives. Host-mode multi-host is not compliant with this requirement.

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-106817r1_fix)
Configure 802.1 x authentications on all host-facing access switch ports. To authenticate 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 RADIUS_1 SW1(config-radius-server)#address ipv4 10.1.22.3 SW1(config-radius-server)#key xxxxxx SW1(config-radius-server)#exit SW1(config)#radius server RADIUS_2 SW1(config-radius-server)#address ipv4 10.1.14.5 SW1(config-radius-server)#key xxxxxx SW1(config-radius-server)#exit Step 2: Enable 802.1x authentication on the switch: SW1(config)#aaa new-model SW1(config)#aaa group server radius RADIUS_SERVERS SW1(config-sg-radius)#server name RADIUS_1 SW1(config-sg-radius)#server name RADIUS_2 SW1(config-sg-radius)#exit SW1(config)#aaa authentication dot1x default group RADIUS_SERVERS SW1(config)#dot1x system-auth-control Step 3: Enable 802.1x on all host-facing interfaces as shown in the example below: SW1(config)#int range g1/0 - 8 SW1(config-if-range)#switchport mode access SW1(config-if-range)#authentication host-mode single-host SW1(config-if-range)#dot1x pae authenticator SW1(config-if-range)#authentication port-control auto SW1(config-if-range)#end Note: Single-host is the default. Host-mode multi-domain (for VoIP phone plus PC) or multi-auth (multiple PCs connected to a hub) can be configured as alternatives.

Fix Text (F-106817r1_fix)

Configure 802.1 x authentications on all host-facing access switch ports. To authenticate 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 RADIUS_1
SW1(config-radius-server)#address ipv4 10.1.22.3
SW1(config-radius-server)#key xxxxxx
SW1(config-radius-server)#exit
SW1(config)#radius server RADIUS_2
SW1(config-radius-server)#address ipv4 10.1.14.5
SW1(config-radius-server)#key xxxxxx
SW1(config-radius-server)#exit

Step 2: Enable 802.1x authentication on the switch:

SW1(config)#aaa new-model
SW1(config)#aaa group server radius RADIUS_SERVERS
SW1(config-sg-radius)#server name RADIUS_1
SW1(config-sg-radius)#server name RADIUS_2
SW1(config-sg-radius)#exit
SW1(config)#aaa authentication dot1x default group RADIUS_SERVERS
SW1(config)#dot1x system-auth-control

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

SW1(config)#int range g1/0 - 8
SW1(config-if-range)#switchport mode access
SW1(config-if-range)#authentication host-mode single-host
SW1(config-if-range)#dot1x pae authenticator
SW1(config-if-range)#authentication port-control auto
SW1(config-if-range)#end

Note: Single-host is the default. Host-mode multi-domain (for VoIP phone plus PC) or multi-auth (multiple PCs connected to a hub) can be configured as alternatives.