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The Arista router must be configured to have Internet Control Message Protocol (ICMP) unreachable notifications disabled on all external interfaces.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-256032ARST-RT-000530SV-256032r882438_ruleCCI-002385medium
Description
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. Host unreachable ICMP messages are commonly used by attackers for network mapping and diagnosis.
STIGDate
Arista MLS EOS 4.X Router Security Technical Implementation Guide2025-02-20

Related Frameworks

1 mapping across 4 frameworks
SCF0 mappings

No source states a mapping between these directly.

Also reachable in 3 hops (13) 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.

MON-01Continuous Monitoring
1.00
MON-01.1Intrusion Detection & Prevention Systems (IDS & IPS)
1.00
MON-01.3Inbound & Outbound Communications Traffic
1.00
MON-01.4System Generated Alerts
1.00
MON-01.8Security Event Monitoring
1.00
NET-01Network Security Controls (NSC)
1.00
NET-02Layered Network Defenses
1.00
SEA-01Secure Engineering Principles
1.00
SEA-02Alignment With Enterprise Architecture
1.00
CAP-01Capacity & Performance Management
0.50

+3 more (top 10 by confidence shown)

NIST 800-530 mappings

No source states a mapping between these directly.

Also reachable in 2 hops (36) 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.

AC-10Concurrent Session Control
1.00
AC-17(9)Disconnect or Disable Access
1.00
AC-2(4)Automated Audit Actions
1.00
AC-3Access Enforcement
1.00
AC-4Information Flow Enforcement
1.00
AC-6(9)Log Use of Privileged Functions
1.00
AU-12Audit Record Generation
1.00
AU-3Content of Audit Records
1.00
AU-5Response to Audit Logging Process Failures
1.00
CM-11(2)Software Installation with Privileged Status
1.00

+26 more (top 10 by confidence shown)

CCI1 mapping
CCI-002385
1.00
NIST CSF 2.00 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.

DE.CM-01
1.00
PR.IR-01
1.00
PR.IR-04
0.50

Who does this work

12 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-256032r882438_chk)

Review the device configuration to determine if controls have been defined to ensure the router does not send ICMP unreachable notifications out to any external interfaces. Step 1: To verify the ACL is configured to determine the router does not send ICMP unreachable notifications out to any external interfaces, execute the command "sh ip access-list". ip access-group DENY_ICMP_UNREACHABLE deny icmp any any unreachable permit ip any any Step 2: To verify the ACL is applied outbound on interfaces, execute the command "sh run int Eth YY". interface Ethernet 2 ip access-group DENY_ICMP_UNREACHABLE out If ICMP unreachable notifications are enabled on any external interfaces, this is a finding.

Fix Text (F-59651r882437_fix)

Disable ICMP unreachable notifications on all external interfaces. Step 1: The Arista router can be configured to filter out the ICMP Unreachable for (Type 3) code 0 (Network unreachable) IPv4 and IPv6 packets with the following command: router(config)#ip icmp rate-limit-unreachable 0 router(config)#ipv6 icmp rate-limit-unreachable 0 Step 2: The Arista router can be configured to filter out the ICMP Unreachable for (Type 3) code 1 (Network unreachable) IPv4 and IPv6 packets with the following command: router(config)#ip access-list BLK-ICMP-Unreachables 10 deny icmp any any host-unreachable 20 permit ip any any ! Step 3: This would need to be applied on the egress interface (for example as in et1 below): router(config)#interface ethernet1 no routerport ip address 32.1.1.12/24 ip access-group BLK-ICMP-Unreachables out !