V-254036

Discussion

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.

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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.

Verify the global "no-redirects" statement is enabled under [edit system] or that individual interface "no-redirects" statements are configured on external interfaces.
[edit system]
no-redirects;
[edit interfaces]
<external interface name> {
    unit <number> {
        family inet {
            no-redirects;
            address <IPv4 address>.<mask>;
        }
        family inet6 {
            no-redirects;
            address <IPv6 address>.<prefix>;
        }
    }
}

If ICMP Redirect messages are enabled on any external interfaces, this is a finding.