Don’t WannaCry on your Industrial IoT System

Pretty much anyone who has a computer or listens to the news has heard about the WannaCry virus that swept across the world a few days ago, installing itself on computers in businesses, hospitals, government agencies, and homes, encrypting hard drives and demanding ransom payments.  After scrambling to ensure that our operating systems are up-to-date and protected against this latest threat, the question soon comes up: How can we protect ourselves against similar threats in the future?

“How?” indeed.  That would seem difficult.  Our reliance on networked computers for business and personal use is fully entrenched, and business/personal PCs will remain vulnerable for the foreseeable future.  In the industrial arena, some may conclude this latest attack is yet another reason to hold off on their IoT strategy.  Or, at least: “You should use a VPN to keep it safe.”

And yet neither of these instincts is necessarily correct because (i) it is possible to build a secure Industrial IoT (“IIoT”) system, and (ii) VPN is not the way to do it.  Industrial control systems may use the same underlying operating systems as PCs but they are different in one critical aspect.  They exchange real-time control data, not files and emails.

How WannaCry Got In

WannaCry comes in two parts – an email “bomb” that exploits your anti-virus software and a “worm” that propagates throughout your network by exploiting configuration weaknesses and operating system bugs.  The special danger of WannaCry is that it can infect a computer through email even if you never open the email message.  Once WannaCry arrives through email, the worm takes over to attack the rest of the computers on your network.

The worm portion of the virus spreads itself by finding other machines on the network.  According to analysis of the code by Zammis Clark at Malwarebytes Labs, “After initializing the functionality used by the worm, two threads are created. The first thread scans hosts on the LAN. … The scanning thread tries to connect to port 445, and if so creates a new thread to try to exploit the system using MS17-010/EternalBlue.” (the bug that the virus exploits)

If there is no open port on the other computer, the virus cannot spread.  But the VPN is not much help here.  If anyone on the VPN is struck by the virus, then every machine on the LAN is exposed.  Suppose you have an IIoT system connecting a corporate office to a process control system over a VPN.  If the virus activates on any of the connected machines in the IT department, it can easily propagate itself to any of the connected machines on the industrial LAN.

How to Keep WannaCry Out

The tongue-in-cheek answer is “don’t use email”.  More seriously, industrial systems and IT systems should be separated from one another.  There is no need to read email from the industrial LAN.  Don’t install email software on your industrial computers, and don’t allow email traffic through your firewall.

But industrial systems still need to communicate their data.  How can you reach the data without exposing the industrial network?  The solution is spelled out in detail in the latest white paper from Cogent (a Skkynet company) titled: Access Your Data, Not Your Network. This paper explains why the traditional architecture of industrial systems is not suitable for secure Industrial IoT or Industrie 4.0 applications, and discusses the inherent risks of using a VPN.  But most important, it introduces the best approach for secure IIoT and Industrie 4.0, which is to provide access to industrial data without exposing the network at all.

Specifically, the Skkynet-provisioned devices and the DataHub can make outbound connections to SkkyHub without opening any firewall ports.  These connections are robust channels that support bidirectional, real-time communications for doing monitoring and supervisory control.  The WannaCry virus or anything similar cannot spread into this system because they can’t see anything to infect.  The devices on the network are completely invisible.  Skkynet’s approach provides access to the data only, not to the network.