Cybersecurity In-Depth

The Edge

Should I Segment My IoT Devices Onto Their Own Networks?

Understanding the criticality and importance of the device determines the level of segmentation.

Question: Should I segment my IoT devices onto their own networks?

Sean Tufts, practice director, product security, ICS and IoT, Optiv: It depends. Some clients are very focused on determining whether a device is operational technology (OT), Internet of Things (IoT), industrial Internet of Things (IIoT), or industrial-control system (ICS) and creating custom environments for them. I'm not really concerned about that. With segmentation, I'm more concerned with criticality and importance of the devices.  

The criticality of the device
An IP camera could be recording a parking lot. It could be recording an operating room inside of a hospital. You need granular details to define security policy. More importantly, you need flexibility for a policy to mold to different needs. The parking lot example might seem simple, but did you think about GDPR? License plates are considered personally identifiable information in the EU. It might be easy to lump an IP camera into an IoT bucket, but it's almost certainly more complicated than that.

The general question of "If the data got loose, would it end up on Reddit?" governs here. If so, it should not run on the general corporate environment. Segment it off. I see clients taking three broad measures:

  • Block the common smart device offenders. Strong network access control (NAC) is a good start here.
  • Create a safe place for new technologies to get access. This includes review by security personnel.
  • Measure risk and criticality to focus your IoT efforts on a smaller list of offenders. These include custom (and often segmented) environments.

The integration and importance of the device
Building maintenance systems is a good illustration of this. Some temperature sensors are irrelevant, but those inside a poultry processing plant are woven into the most important controls of the facility. More importantly, the range of operating conditions goes from freezing to boiling, so the architecture needs to be dynamic. No one wants warm, raw chicken breasts. Any IT configurations in the plant have an impact on these ranges. These IoT systems cannot be wholly segmented because of their importance in the ecosystem. This is a place to focus building bridges between security and production.