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

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-272079CACI-RT-000019SV-272079r1168423_ruleCCI-001097medium
Description
Fragmented ICMP packets can be generated by hackers for denial-of-service (DoS) attacks such as Ping O' Death and Teardrop. It is imperative that all fragmented ICMP packets are dropped.
STIGDate
Cisco ACI Router Security Technical Implementation Guide2025-12-11

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
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.

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-272079r1168423_chk)

If this review is for the DODIN Backbone, mark as Not Applicable. When creating a contract, create a Deny statement that looks at all the fragmented bits and denies only those packets. Review the following two locations: Option 1: Review any standard contract (whitelist) with an explicit deny for the fragment bit to counter act any allows. Tenant >> Contracts >> Standard >> {{your_Contract}} >> {{your_contract_Subject}} >> Policy >> General >> Filters >> create/ add a deny for ICMP traffic. The filter entries should include the following: Ethertype set to IP/ipv6, IP Protocol set to ICMP/ICMPv6, and the Match Only Fragments box checked. Option 2: Review any taboo contract (blacklist) for the fragment bits: Tenant >> Contracts >> Taboo >> {{your_Contract}} >> Policy >> General >> {{your_contract_Subject}} >> Filters >> create/ add a deny for ICMP traffic. The filter entries should include the following: Ethertype set to IP/ipv6, IP Protocol set to ICMP/ICMPv6, and the Match Only Fragments box checked3. Verify ICMP and Fragmented are selected to be denied. If all fragmented ICMP packets destined to Cisco ACI IP addresses are not dropped, this is a finding.

Fix Text (F-76036r1168422_fix)

Place the deny rule before any permit rules for ICMP traffic to ensure fragmented ICMP packets are dropped first. When you are creating a contract you would want to create a Deny statement that looks at all the fragmented bits and denies only those packets. There are 2 ways to do this. Option 1: Create a standard contract (whitelist) with an explicit deny for the fragment bit to counter act any allows. Navigate to the following location and configure settings: Tenant >> Contracts >> Standard >> {{your_Contract}} >> {{your_contract_Subject}} >> Policy >> General >> Filters >> create/ add a deny for ICMP traffic. The filter entries should include the following: Ethertype set to IP/ipv6, IP Protocol set to ICMP/ICMPv6, and the Match Only Fragments box checked. Option 2: Create a taboo contract (blacklist) for the fragment bits by navigating to the following location: Tenant >> Contracts >> Taboo >> {{your_Contract}} >> Policy >> General >> {{your_contract_Subject}} >> Filters >> create/ add a deny for ICMP traffic. The filter entries should include the following: Ethertype set to IP/ipv6, IP Protocol set to ICMP/ICMPv6, and the Match Only Fragments box checked.