3.5 Dynamic ARP Inspection

Information

Dynamic ARP Inspection (DAI) is a security feature available in AOS-CX switches that validates ARP packets on the network to prevent ARP spoofing and ARP-based man-in-the-middle attacks. It verifies ARP requests and responses against trusted sources, such as DHCP snooping and static ARP entries.

Dynamic ARP inspection ensures that ARP traffic is authenticated before being forwarded, preventing attackers from injecting forged ARP packets to redirect traffic. This feature is critical in maintaining the integrity of Layer 2 networks and protecting devices from malicious attempts to hijack IP addresses.

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

Solution

Following command enables Dynamic ARP inspection on the current VLAN, which means that ARP packets received from untrusted interfaces are discarded if they have an Invalid IP-to-MAC address binding -

switch(config)# vlan <vlan-id>
switch(config-vlan)# arp inspection

Configures the interface as a trusted. All interfaces are untrusted by default -

switch(config)# interface <interface-id>
switch(config-if)# arp inspection trust

Dynamic ARP Inspection is enforced using DHCP Snooping binding and Static IP Binding. Refer to theDHCP Snooping section for the DHCP snooping configuration. To enable the Static IP Binding use the below configuration -

switch(config)# vlan <vlan-id>
switch(config-vlan)# arp ipv4 <IPV4_ADDR> mac <MAC_ADDR>

Impact:

Implementing Dynamic ARP Inspection enhances network security by blocking malicious ARP packets and mitigating risks of ARP-based attacks. It reduces downtime caused by compromised devices and ensures reliable communication in enterprise environments. However, misconfiguration or lack of trusted entries may disrupt legitimate traffic.

See Also

https://workbench.cisecurity.org/benchmarks/24202

Item Details

Category: SECURITY ASSESSMENT AND AUTHORIZATION, SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|CA-9, 800-53|SC-7, 800-53|SC-7(5), CSCv7|12.4

Plugin: ArubaOS

Control ID: 8830c221ee4bded99db49c9d37beb757748b77338ae6662659487bb801136d1d