The Cisco router must be configured to have Internet Control Message Protocol (ICMP) redirect messages disabled on all external interfaces.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-216748 | CISC-RT-000190 | SV-216748r856439_rule | Medium |
| Description |
| The ICMP supports IP traffic by relaying information about paths, routes, and network conditions. Routers automatically send ICMP messages under a wide variety of conditions. Redirect ICMP messages are commonly used by attackers for network mapping and diagnosis. |
| STIG | Date |
| Cisco IOS XR Router RTR Security Technical Implementation Guide | 2024-08-22 |
Details
| Check Text (C-17980r288633_chk) |
| Review the router configuration to verify that ipv4 redirects command has not been configured on any external interface as shown in the example below. interface GigabitEthernet0/0/0/1 ipv4 address x.11.1.2 255.255.255.252 ipv4 redirects If ICMP Redirect messages are enabled on any external interfaces, this is a finding. |
| Fix Text (F-17978r288634_fix) |
| Disable ICMP redirects on all external interfaces as shown in the example below. RP/0/0/CPU0:R3(config)#int g0/0/0/1 RP/0/0/CPU0:R3(config-if)#no ipv4 redirects |