The Cisco router must be configured to have Gratuitous ARP disabled on all external interfaces.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
|---|---|---|---|---|
| V-96527 | CISC-RT-000150 | SV-105665r1_rule | 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 IOS Router RTR Security Technical Implementation Guide | 2019-07-25 |
Details
| Check Text ( C-95363r1_chk ) |
|---|
| Review the configuration to determine if gratuitous ARP is disabled. The following command should not be found in the router configuration: ip gratuitous-arps Note: With Cisco IOS, Gratuitous ARP is enabled and disabled globally. If gratuitous ARP is enabled on any external interface, this is a finding. |
| Fix Text (F-102203r1_fix) |
|---|
| Disable gratuitous ARP as shown in the example below: R5(config)#no ip gratuitous-arps |