Detections
Analytics

JUEX-L2-000140 - The Juniper EX switch must be configured to enable Dynamic Address Resolution Protocol (ARP) Inspection (DAI) on all user VLANs with active access interfaces.

Information

DAI intercepts ARP requests and verifies that each of these packets has a valid IP-to-MAC address binding before updating the local ARP cache and before forwarding the packet to the appropriate destination. Invalid ARP packets are dropped and logged. DAI determines the validity of an ARP packet based on valid IP-to-MAC address bindings stored in the DHCP snooping binding database. If the ARP packet is received on a trusted interface (e.g., access interface with a valid binding or a trunked interface), the switch forwards the packet without any checks. On untrusted interfaces, the switch forwards the packet only if it is valid.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

Configure the switch to have DAI enabled on all user VLANs with active access interfaces.

1. Enter configuration mode.
2. Configure user-facing or untrusted VLANs with active access interfaces with DAI.
3. Commit the configuration.

user@host> configure
Entering configuration mode

user@host# set vlans <untrusted VLAN name> vlan-id <untrusted VLAN ID>

user@host# set vlans <untrusted VLAN name> forwarding-options dhcp-security arp-inspection

user@host# commit
commit complete

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Juniper_EX_Switches_Y26M07_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-5, CAT|II, CCI|CCI-002385, Rule-ID|SV-253961r1212017_rule, STIG-ID|JUEX-L2-000140, Vuln-ID|V-253961

Plugin: Juniper

Control ID: 5cdfada631e344f137641c96ef23e4d20c156b95cf0b69ea2b39499e4a40ae9a