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

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-216744CISC-RT-000140SV-216744r531087_ruleCCI-001097medium
Description
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.
STIGDate
Cisco IOS XR Router RTR Security Technical Implementation Guide2025-08-19

Related Frameworks

1 mapping across 5 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (18) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

CFG-02Secure Baseline Configurations
1.00
CRY-01Use of Cryptographic Controls
1.00
CRY-01.1Alternate Physical Protection
1.00
CRY-03Transmission Confidentiality
1.00
CRY-04Transmission Integrity
1.00
CRY-05Encrypting Data At Rest
1.00
DCH-01Data Protection
1.00
IAC-21Least Privilege
1.00
MON-01Continuous Monitoring
1.00
MON-01.1Intrusion Detection & Prevention Systems (IDS & IPS)
1.00

+8 more (top 10 by confidence shown)

NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (10) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

CM-6Configuration Settings
1.00
SC-24Fail in Known State
1.00
SC-47Alternate Communications Paths
1.00
SC-5Denial-of-service Protection
1.00
SC-7Boundary Protection
1.00
SC-7(11)Restrict Incoming Communications Traffic
1.00
SC-7(29)Separate Subnets to Isolate Functions
1.00
SC-7(5)Deny by Default — Allow by Exception
1.00
SI-4System Monitoring
1.00
SI-4(11)Analyze Communications Traffic Anomalies
1.00
NIST 800-1710 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (3) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

3.13.1
1.00
3.13.2
1.00
3.13.5
1.00
CCI1 mapping
CCI-001097
1.00
NIST CSF 2.00 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (5) derived by us, not asserted by any source

Each of these is a route we composed by chaining published mappings. No publisher states a relationship between the two endpoints.

DE.CM-01
1.00
PR.DS-01
1.00
PR.DS-02
1.00
PR.DS-10
1.00
PR.IR-01
1.00

Who does this work

15 NICE work roles and 9 EC-Council certifications.

This is an inference across published mappings, not a single claim by anyone. This check maps to a control, which maps to a Cybersecurity Framework outcome, which NIST assigns to the work roles below. EC-Council separately maps its certifications to those same roles.

A certification prepares someone for a role. It is not evidence that a holder is qualified, and neither NIST nor EC-Council has stated that any certification here addresses this check.

Work-role assignments published by NIST (NICE Framework Components 2.2.0 and the CSF 2.0 OLIR crosswalk). Certification mappings published by EC-Council.

Details

Check Text (C-216744r531087_chk)

Review the external and internal ACLs to verify that the router is configured to drop all fragmented ICMP packets destined to itself. ipv4 access-list EXTERNAL_ACL_INBOUND 10 permit tcp host x.11.1.1 eq bgp host x.11.1.2 20 permit tcp host x.11.1.1 host x.11.1.2 eq bgp 25 deny icmp any host x.11.1.2 fragments log 30 permit icmp host x.11.1.1 host x.11.1.2 echo 40 permit icmp host x.11.1.1 host x.11.1.2 echo-reply 50 deny ipv4 any host x.11.1.1 log 60 permit tcp any any established … … … 140 deny ipv4 any any log ! ipv4 access-list INTERNAL_ACL_INBOUND 5 deny icmp any any fragments 10 permit icmp any host 10.1.12.2 fragments 20 permit ospf host 10.1.12.1 host 10.1.12.2 30 permit tcp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq ssh 40 permit tcp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq tacacs 50 permit udp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq snmp 60 permit udp 10.2.1.0 0.0.0.255 host 10.1.12.2 eq ntp 70 deny ipv4 any host 10.1.12.2 log … … … 110 permit ip any any Note: Ensure the statement to deny ICMP fragments is before any permit statements for ICMP. If the router is not configured to drop all fragmented ICMP packets destined to itself, this is a finding.

Fix Text (F-17974r288622_fix)

Configure the external and internal ACLs to drop all fragmented ICMP packets destined to itself as shown in the example below. RP/0/0/CPU0:R3(config)#ipv4 access-list EXTERNAL_ACL_INBOUND RP/0/0/CPU0:R2(config-ipv4-acl)#25 deny icmp any host x.11.1.2 fragments log RP/0/0/CPU0:R3(config)#ipv4 access-list INTERNAL_ACL_INBOUND RP/0/0/CPU0:R2(config-ipv4-acl)#5 deny icmp any host 10.1.12.2 fragments log Note: Ensure the above statement is before any permit statements for ICMP.