Bolster your defenses.

The Ukraine crisis will almost certainly raise the cyber security risk for the of rest Europe. The sanctions imposed on Russia demand an increased awareness and defense effort for securing the OT systems. These sanctions will hurt and shall undoubtedly become an incentive for an organized revenge from very capable threat actors. What could be more effective for them than cyberattacks at a safe distance.

I think all energy-related installations such as for example port terminals, pipelines, gas distribution, and possibly power will have to raise their level of alertness. Until now, most attacks have focused on the IT systems, but that does not mean that IT systems are the only targets and the OT systems are safe. Attacking the OT systems can cause a much longer downtime than a ransomware attack or wiping disk drives would, so such an attack might be seen as a strong warning signal.

Therefor it is important to bolster our defenses. Obviously we don’t have much time, so our response should be short term, structural improvements just take too much time. So what can be done?


Let’s create a list of possible actions that we could take today if we want to brace ourselves against potential cyber attacks:

  • Review all OT servers / desktops that have a connection with an external network. External including the corporate network and partner networks. We should make sure that these servers have the latest security patches installed. Let’s at minimum remove the well known vulnerabilities.
  • Review the firewall and make certain they run the latest software version.
  • Be careful which side you manage the firewall from, managing from the outside is like putting your front door key under the mat.
  • Review all remote connections to service providers. Such connections should be free from:
    • Open inbound connections. An inbound channel can often be exploited, more secure remote access solutions poll the outside world for remote access requests preventing any open inbound connections.
    • Automatic approvals on access requests, make sure that every request is validated prior to approval for example using a voice line.
  • Modify your access credentials for the remote access systems, they might have been compromised in the past. Use strong passwords of sufficient length (10+) and character variation. Better is of course to combine this with two-factor authentication, but if you don’t have this today it would take too much time to add it. Would be a mid-term improvement, this list is about easy steps to do now.
  • Review the accounts that have access, remove stale accounts not in use.
  • Apply the least privilege principle. Wars make the insider threat more likely to happen, enforcing the least privilege principle will raise the hurdle.
  • Ensure you have session time outs implemented, to prevent that sessions remain open when they are not actively used.
  • Review the remote server connections. If there are inbound open ports required make sure the firewall restricts access as much as possible using at minimum IP address filters and TCP port filters. But better would be (if you have a next generation firewall in place) to add further restrictions such as restricting the access to a specific account.
  • Review your antivirus to have the latest signature files, the same for your IPS vaccine files.
  • Make certain you have adequate and up-to-date back-ups available. Did you ever test to restore a back-up?
    • You should have multiple back-ups, at minimum 3. It is advised to store the back-ups on at least 2 different media, don’t have both back-ups online accessible.
    • Make sure they can be restored on new hardware if you are running legacy systems.
    • Make sure you have a back-up or configuration sheet for every asset.
  • Hardening your servers and desk tops is also important, but if you never did this it might take some time to find out which services can be disabled and which services are essential for the server / desk top applications. So probably a mid-term activity, but reducing the attack surface is always a good idea.
  • Have your incident response plan ready at hand, and communicated throughout the organization. Ready at hand, meaning not on the organizational network. Have hardcopies available. Be sure to have updated contact lists and plan to have communications using non-organizational networks and resources. (Added by Xander van der Voort)

I don’t know if I missed some low hanging fruit, if so please respond to the blog so I can make the list more complete. This list should mention the easy things to do, just configuration changes or some basic maintenance. Something that can be done today if we would find the time.


Of course, our cyber worries are of a totally different order than the people in Ukraine are now experiencing for their personal survival and their survival as an independent nation. However the OT cyber community in Europe must also take responsibility and map out where our OT installations can be improved / repaired in a short time, to reduce risk.

Cyber wars have no borders, so we should be prepared.

And of course I shouldn’t forget my focus on OT risk. A proper risk assessment would bring you an insight in what threat actions (at TTP level) you can expect, and for which of these you already have controls in place. In situations like we are in now, this would be a great help to quickly review the security posture and perhaps adjust our risk appetite a bit to further tighten our controls.

However if you haven’t done a risk assessment at this level of detail today, it isn’t feasible to do this short term therefore it is not in the list. All I could do is going over the hundreds of bow-ties describing the attack scenarios and try to identify some quick wins that raise the hurdle a bit. I might have missed some, but I hope that the community corrects me so I can add them to the list. A good list of actions to bolster our defenses is of practical use for everyone.

I am not the guy that is easily scared by just another log4j story, but now I think we have to raise our awareness and be ready to face some serious challenges on our path. So carefully review where the threat actor might find weaknesses in your defense and start fixing them.


There is no relationship between my opinions and references to publications in this blog and the views of my employer in whatever capacity. This blog is written based on my personal opinion and knowledge build up over 43 years of work in this industry. Approximately half of the time working in engineering these automation systems, and half of the time implementing their networks and securing them, and conducting cyber security risk assessments for process installations since 2012.


Author: Sinclair Koelemij

OTcybersecurity web site

4 thoughts on “Bolster your defenses.”

  1. Have your incident response plan ready at hand, and communicated throughout the organization. Ready at hand, meaning not on the organizational network. Have hardcopies available. Be sure to have updated contact lists and plan to have communications using non-organizational networks and resources. Don’t produce plans > 10 pages. They are useles.

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