The Cisco switch 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
mediumV-221085SRG-NET-000362-RTR-000115CISC-RT-000190SV-221085r999694_rule2024-12-203
Description
The ICMP supports IP traffic by relaying information about paths, routes, and network conditions. Switches 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 switch configuration to verify that the no ip redirects command has been configured on all external interfaces as shown in the example below: interface Ethernet2/7 no switchport ip address x.22.4.2/30 no ip 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: SW1(config)# int e2/7 SW1(config-if)# no ip redirects