The Cisco router must be configured to have Internet Control Message Protocol (ICMP) redirect messages disabled on all external interfaces.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-216748 | SRG-NET-000362-RTR-000115 | CISC-RT-000190 | SV-216748r856439_rule | 2024-08-22 | 3 |
| 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. |
| ℹ️ Check |
|---|
| 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 |
|---|
| 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 |