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V-221085

CAT II (Medium)

The Cisco switch must be configured to have Internet Control Message Protocol (ICMP) redirect messages disabled on all external interfaces.

Rule ID

SV-221085r999694_rule

STIG

Cisco NX OS Switch RTR Security Technical Implementation Guide

Version

V3R4

CCIs

CCI-002385

Discussion

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.

Check Content

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 Text

Disable ICMP redirects on all external interfaces as shown in the example below:

SW1(config)# int e2/7
SW1(config-if)# no ip redirects