The router must be configured to have Internet Control Message Protocol (ICMP) redirects disabled on all external interfaces.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-78227	SRG-NET-000362-RTR-000115	SV-92933r1_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
Router Security Requirements Guide	2019-09-27

Details

Check Text ( C-77783r1_chk )
Review the device configuration to determine if controls have been defined to ensure the router does not send ICMP Redirect messages out to any external interfaces. If ICMP Redirect messages are enabled on any external interfaces, this is a finding.

Fix Text (F-84955r1_fix)
Disable ICMP redirects on all external interfaces.