Stop ARP Spoofing on NI myRIO

TL;DR

ARP spoofing lets attackers intercept network traffic by faking MAC addresses. This guide shows you how to detect and prevent it on your National Instruments (NI) myRIO device, using a combination of static ARP entries and monitoring tools.

What is ARP Spoofing?

ARP (Address Resolution Protocol) translates IP addresses into MAC addresses. Spoofing involves an attacker sending fake ARP messages to associate their MAC address with the IP address of another device on your network, like your myRIO or gateway. This redirects traffic intended for that device through the attacker’s machine.

How to Detect and Prevent ARP Spoofing

1. Understand Your Network
• Know the IP address of your myRIO. You can find this in the NI MAX software or via the myRIO’s web interface.
• Identify the MAC address of your myRIO. This is also available in NI MAX and the web interface.
• Note the IP and MAC addresses of your default gateway (router).
2. Static ARP Entries

The most effective prevention method is to create static ARP entries on devices that communicate with the myRIO, especially your router/gateway. This tells them to always associate a specific IP address with the correct MAC address.

• On Linux: Use the arp command.

  sudo arp -s [IP_address] [MAC_address]

  For example:

  sudo arp -s 192.168.1.10 AA:BB:CC:DD:EE:FF

  (Replace with your myRIO’s IP and MAC address.)

• On Windows: Use the arp -a command to view existing entries, then add a static entry using:

  arp -s [IP_address] [MAC_address]

  For example:

  arp -s 192.168.1.10 AA:BB:CC:DD:EE:FF

  (Replace with your myRIO’s IP and MAC address.)

• On macOS: Use the following command:

  sudo arp -d [IP_address]

  to delete any existing entry, then add a static one using:

  sudo arp -s [IP_address] [MAC_address]

  For example:

  sudo arp -s 192.168.1.10 AA:BB:CC:DD:EE:FF

3. ARP Monitoring Tools

Regularly check your ARP table for inconsistencies.

• Linux: Use arp -a to view the current ARP table. Look for duplicate IP addresses with different MAC addresses.

  arp -a

• Windows: Use arp -a in the command prompt. Again, check for duplicates.

  arp -a

• Wireshark: A powerful network protocol analyser. Capture traffic and filter by ARP to identify suspicious activity. Look for multiple ARP replies for the same IP address.
4. myRIO Security Considerations
• Keep your myRIO’s firmware up-to-date. Updates often include cyber security improvements.
• Use strong passwords and restrict access to the web interface.
• If possible, segment your network so that the myRIO is on a separate VLAN or subnet from more sensitive devices.
5. Automated Monitoring (Advanced)

For continuous monitoring, consider scripting regular ARP table checks and alerting you to any changes. This requires some programming knowledge.