The Cisco switch must be configured to have Gratuitous ARP disabled on all external interfaces.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-221082 | CISC-RT-000150 | SV-221082r999691_rule | CCI-002385 | medium |
| Description | ||||
| A gratuitous ARP is an ARP broadcast in which the source and destination MAC addresses are the same. It is used to inform the network about a host IP address. A spoofed gratuitous ARP message can cause network mapping information to be stored incorrectly, causing network malfunction. | ||||
| STIG | Date | |||
| Cisco NX OS Switch RTR Security Technical Implementation Guide | 2024-12-20 | |||
Details
Check Text (C-221082r999691_chk)
Review the configuration to determine if gratuitous ARP is disabled on all external interfaces as shown in the example below:
interface Ethernet2/7
no switchport
ip address x.22.4.2/30
no ip arp gratuitous request
Note: Gratuitous ARP is enabled on all interfaces by default.
If gratuitous ARP is enabled on any external interface, this is a finding.
Fix Text (F-22786r409736_fix)
Disable Gratuitous ARP as shown in the example below:
SW1(config)# int e2/7
SW1(config-if)# no ip arp gratuitous request
SW1(config-if)# end