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Edge Ask The Experts

8/17/2020
01:45 PM
Sean Tufts
Sean Tufts
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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.

 

Sean Tufts is the practice director for the OT/IOT business at Optiv. He's a former NFL linebacker turned critical infrastructure security leader. Post NFL, he worked for utility operators and O&G hardware suppliers. Prior to his current leadership position at Optiv, Sean was ...
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tdsan
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tdsan,
User Rank: Ninja
8/20/2020 | 5:19:39 PM
I agree with the writer, but Sean Tufts (not so sure)
I'm not really concerned about that. With segmentation, I'm more concerned with the criticality and importance of the devices. --Sean Tuffs

 I am not sure if I agree with this reasoning, there is a thing called Zero-Trust especially for environments like hospitals, police stations, utility companies, and IT companies who should have these devices in an isolated environment or VLAN (VXLAN in some cases - VMware Centric). If configured properly, you only allow specific devices to communicate with those devices over a secured connection. I think IPv6 is good to secure devices like this (IoT Devices) because they add an additional layer to the network (IPv6 AES256 IPSec ESP/AH Tunnels). The writer stated that the user should have strong NAC (I agree) with tools to limit the execution of executables on the network so it limits ransomware and external threats and attacks.

 

evolution-of-smart-buildings-and-their-place-in-the-internet-of ...

 

This is an example but it gives the reader an idea of the various devices that could exist in any sort of environment. We need to start thinking of Zero-trust designs using locked down methods where baselines of servers and IoT devices are segmented with only a few devices to communicate with servers and/or telecom/network devices.

But think about this, if I can modify the settings on a PLC device, then I can change water temperature, heating/cooling, electrical regulation, so that means those devices need to be isolated because their security posture will not be as high as those in Zone 0 or 1.

The Purdue model for Industrial control systems - Industrial ...

 

So to me, it is not only about the importance of the device, but where the device is located in the IT ecosystem and its function. There needs to be a conversation so if there is any doubt in your mind, then you may need to fortify the design of the network with MFA/2FA, limit who has access to certain devices, if there is a need, put them on a VLAN where VLANs from the admin staff is part of the multi-connect VLAN or VXLAN, and finally, the vendor needs to be consulted to share with them any shortcomings you find (Continuous Diagnostic and Mitigation - CDM).

T

 

 
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