ARST-RT-000540 - The Arista router must be configured to have Internet Control Message Protocol (ICMP) mask replies disabled on all external interfaces.

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Information

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. Mask Reply ICMP messages are commonly used by attackers for network mapping and diagnosis.

Solution

Step 1: Disable ICMP mask replies on all external interfaces.

ip access-group DENY_ICMP_MASK_REPLY
deny icmp any any mask-reply
permit ip any any

Step 2: Apply the ACL outbound on interfaces.

interface Ethernet 2
ip access-group DENY_ICMP_MASK_REPLY out

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Arista_MLS_EOS_4-2x_Y23M02_STIG.zip

Item Details

References: CAT|II, CCI|CCI-002385, Rule-ID|SV-256033r882441_rule, STIG-ID|ARST-RT-000540, Vuln-ID|V-256033

Plugin: Arista

Control ID: 319f060b6a4df042e6e8013aa12b41f9d18c16d03d0e94478c98c6c921fd4956