Title

The router must be configured to drop all fragmented Internet Control Message Protocol (ICMP) packets destined to itself. (Cat II impact)

Discussion

Fragmented ICMP packets can be generated by hackers for DoS attacks such as Ping O' Death and Teardrop. It is imperative that all fragmented ICMP packets are dropped.

Check Content

Review the access control list (ACL) or filter for the router receive path. Verify that it will drop all fragmented ICMP packets destined to itself. If the router is not configured with a receive-path filter to drop all fragmented ICMP packets, this is a finding. Note: If the platform does not support the receive path filter, verify that all Layer 3 interfaces have an ingress ACL to control what packets are allowed to be destined to the router for processing.

Fix Text

Ensure all routers have their receive path filter configured to drop all fragmented ICMP packets.

Additional Identifiers

Rule ID: SV-207134r604135_rule

Vulnerability ID: V-207134

Group Title: SRG-NET-000205

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.