STIGQter: STIG Summary: Cisco IOS Switch L2S Security Technical Implementation Guide Version: 2 Release: 1 Benchmark Date: 23 Apr 2021:

The Cisco switch must have all disabled switch ports assigned to an unused VLAN.

DISA Rule

SV-220641r539671_rule

Vulnerability Number

V-220641

Group Title

SRG-NET-000512-L2S-000007

Rule Version

CISC-L2-000210

Severity

CAT II

CCI(s)

• CCI-000366 - The organization implements the security configuration settings.

Weight

10

Fix Recommendation

Assign all switch ports not in use to an inactive VLAN.

Step 1: Assign the disabled interfaces to an inactive VLAN:

SW3(config)#int range g0/0 – 9
SW3(config-if-range)# switchport access vlan 999

Step 2: Configure trunk links to not allow traffic from the inactive VLAN:

SW3(config)#int g1/1
SW3(config-if)#switchport trunk allowed vlan except 999

Check Contents

Step 1: Review the switch configurations and examine all access switch ports. Each access switch port not in use should have membership to an inactive VLAN.

interface GigabitEthernet0/0
switchport access vlan 999
shutdown
!
interface GigabitEthernet0/1
switchport access vlan 999
shutdown
…
…
…
interface GigabitEthernet0/9
switchport access vlan 999
shutdown

Step 2: Verify that traffic from the inactive VLAN is not allowed on any trunk links as shown in the example below:

interface GigabitEthernet1/1
switchport trunk allowed vlan 1-998,1000-4094
switchport trunk encapsulation dot1q
switchport mode trunk

Note: Switch ports configured for 802.1x are exempt from this requirement.

If any access switch ports are not in use and not in an inactive VLAN, this is a finding.

Vulnerability Number

V-220641

Documentable

False

Rule Version

CISC-L2-000210

Severity Override Guidance

Step 1: Review the switch configurations and examine all access switch ports. Each access switch port not in use should have membership to an inactive VLAN.

interface GigabitEthernet0/0
switchport access vlan 999
shutdown
!
interface GigabitEthernet0/1
switchport access vlan 999
shutdown
…
…
…
interface GigabitEthernet0/9
switchport access vlan 999
shutdown

Step 2: Verify that traffic from the inactive VLAN is not allowed on any trunk links as shown in the example below:

interface GigabitEthernet1/1
switchport trunk allowed vlan 1-998,1000-4094
switchport trunk encapsulation dot1q
switchport mode trunk

Note: Switch ports configured for 802.1x are exempt from this requirement.

If any access switch ports are not in use and not in an inactive VLAN, this is a finding.

Check Content Reference

M

Target Key

4070

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