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 Unknown Unicast Flood Blocking (UUFB) enabled.

DISA Rule

SV-220632r539671_rule

Vulnerability Number

V-220632

Group Title

SRG-NET-000362-L2S-000024

Rule Version

CISC-L2-000120

Severity

CAT II

CCI(s)

• CCI-002385 - The information system protects against or limits the effects of organization-defined types of denial of service attacks by employing organization-defined security safeguards.

Weight

10

Fix Recommendation

Configure the switch to have UUFB enabled as shown in the configuration example below:

SW1(config)#int range g0/0 - 9
SW1(config-if-range)#switchport block unicast

Check Contents

Review the switch configuration to verify that UUFB is enabled on all access switch ports as shown in the configuration example below:

interface GigabitEthernet0/0
switchport block unicast
!
interface GigabitEthernet0/1
switchport block unicast
…
…
…
interface GigabitEthernet0/9
switchport block unicast

If any access switch ports do not have UUFB enabled, this is a finding.

Vulnerability Number

V-220632

Documentable

False

Rule Version

CISC-L2-000120

Severity Override Guidance

Review the switch configuration to verify that UUFB is enabled on all access switch ports as shown in the configuration example below:

interface GigabitEthernet0/0
switchport block unicast
!
interface GigabitEthernet0/1
switchport block unicast
…
…
…
interface GigabitEthernet0/9
switchport block unicast

If any access switch ports do not have UUFB enabled, this is a finding.

Check Content Reference

M

Target Key

4070

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