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

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_Y24M07_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-5, CAT|II, CCI|CCI-002385, Rule-ID|SV-256033r882441_rule, STIG-ID|ARST-RT-000540, Vuln-ID|V-256033

Plugin: Arista

Control ID: fe0b2f77b0ee1dcb8872172197443c4deb6ed5c895d97cc64231c4c46c013d86