Cisco IOS Router
| AID | 7 |
|---|---|
| Severity | medium |
| Audit | The Cisco router must be configured to have Internet Control Message Protocol (ICMP) mask reply messages disabled on all external interfaces. |
| Guidance | 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. Mask Reply ICMP messages are commonly used by attackers for network mapping and diagnosis. |
| Recommendations | Disable ip mask-reply on all external interfaces as shown below. R4(config)#int g0/1 |
| Procedure | Review the router configuration and verify that ip mask-reply command is not enabled on any external interfaces as shown in the example below. interface GigabitEthernet0/1 If the ip mask-reply command is configured on any external interface, this is a finding. |
| NIST SP 800-53 Rev. 4 | Protect against or limit the effects of organization-defined types of denial of service events. |
| STIG | Cisco IOS Router RTR Release: 3 Benchmark Date: 30 Jan 2025 |
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