Finding ID | Version | Rule ID | IA Controls | Severity |
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V-256034 | ARST-RT-000550 | SV-256034r882444_rule | Medium |
Description |
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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. |
STIG | Date |
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Arista MLS EOS 4.2x Router Security Technical Implementation Guide | 2023-01-17 |
Check Text ( C-59710r882442_chk ) |
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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. Step 1: To verify the ACL is configured to determine the router does not send ICMP Redirect messages out to any external interfaces, execute the command "sh ip access-list". ip access-group DENY_REDIRECT deny icmp any any redirect permit ip any any Step 2: To verify the ACL is applied outbound on interface, execute the command "sh run int Eth YY". interface Ethernet 2 ip access-group DENY_REDIRECT out If ICMP Redirect messages are enabled on any external interfaces, this is a finding. |
Fix Text (F-59653r882443_fix) |
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Step 1: Disable ICMP redirects on all external interfaces. ip access-group DENY_REDIRECT deny icmp any any redirect permit ip any any Step 2: Apply the ACL outbound on interfaces. interface Ethernet 2 description EXTERNAL INTERFACE ip access-group DENY_REDIRECT in |