Detections
Analytics

1.8 CISC-RT-000170

Information

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

GROUP ID: V-216746RULE ID: SV-216746r856437

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. Host unreachable ICMP messages are commonly used by attackers for network mapping and diagnosis.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

Disable ip unreachables on all external interfaces as shown below.

RP/0/0/CPU0:R3(config)#int g0/0/0/1RP/0/0/CPU0:R3(config-if)#ipv4 unreachables disable

Alternative - DODIN Backbone

Configure the PE router to rate limit ICMP unreachable messages as shown in the example below.

RP/0/0/CPU0:R3(config)#icmp ipv4 rate-limit unreachable df 1000RP/0/0/CPU0:R3(config)#icmp ipv4 rate-limit unreachable 60000RP/0/0/CPU0:R3(config)#end

See Also

https://workbench.cisecurity.org/benchmarks/23599

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-5, CAT|II, CCI|CCI-002385, Rule-ID|SV-216746r856437_rule, STIG-ID|CISC-RT-000170, Vuln-ID|V-216746

Plugin: Cisco

Control ID: 375ecdaed52b5725fc9413ee09eecfe70a90ea2e403fc38ec0bd25b3ee52835d