Tag Archive for: IT/OT

Purdue 2.0: Exploring a New Model for IT/OT Management

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Developed in 1992 by Theodore J. Williams and the Purdue University Consortium, the Purdue diagram — itself a part of the Purdue Enterprise Reference Architecture (PERA) — was one of the first models used to map data flows in computer-integrated manufacturing (CIM).

By defining six layers that contain both information technology (IT) and operational (OT) technology, along with a demilitarized zone (DMZ) separating them, the Purdue diagram made it easier for companies to understand the relationship between IT and OT technologies and establish effective access controls to limit total risk.

As OT technologies have evolved to include network-enabled functions and outward-facing connections, however, it’s time for companies to prioritize a Purdue update that puts security front and center.

The Problem with Purdue 1.0

A recent Forbes piece put it simply: “The Purdue model is dead. Long live, Purdue.”

This paradox is plausible, thanks to the ongoing applicability of Purdue models. Even if they don’t quite match the reality of IT and OT deployments, they provide a reliable point of reference for both IT and OT teams.

The problem with Purdue 1.0 stems from its approach to OT as devices that have MAC addresses but no IP addresses. Consider programmable logic controllers (PLCs). These PLCs typically appear on MAC addresses in Layer 2 of a Purdue diagram. This need for comprehensive visibility across OT and IT networks, however, has led to increased IP address assignment across PLCs, in turn making them network endpoints rather than discrete devices.

There’s also an ongoing disconnect between IT and OT approaches. Where IT teams have spent years looking for ways to bolster both internal and external network security, traditional OT engineers often see security as an IT-only problem. The result is IP address assignment to devices but no follow-up on who can access the devices and for what purpose. In practice, this limits OT infrastructure visibility while creating increased risk and security concerns, especially as companies are transitioning more OT management and monitoring to the cloud.

Adopting a New Approach to Purdue

As noted above, the Purdue diagram isn’t dead, but it does need an update. Standards such as ISA/IEC 62443 offer a solid starting point for computer-integrated manufacturing frameworks, with a risk-based approach that assumes any device can pose a critical security risk and that all classes of devices across all levels must be both monitored and protected. Finally, it takes the position that communication between devices and across layers is necessary for companies to ensure CIM performance.

This requires a new approach to the Purdue model that removes the distinction between IT and OT devices. Instead of viewing these devices as separate entities on a larger network, companies need to recognize that the addition of IP addresses in Layer 2 and even Layer 1 devices creates a situation where all devices are equally capable of creating network compromise or operational disruption.

In practice, the first step of Purdue 2.0 is complete network mapping and inventory. This means discovering all devices across all layers, whether they have a MAC address, IP address, or both. This is especially critical for OT devices because, unlike their IT counterparts, they rarely change. In some companies, ICS and SCADA systems have been in place for 5, 10, even 20 years or more, while IT devices are regularly replaced. As a result, once OT inventory is completed, minimal change is necessary. Without this inventory, however, businesses are flying blind.

Inventory assessment also offers the benefit of in-depth metric monitoring and management. By understanding how OT devices are performing and how this integrates into IT efforts, companies can streamline current processes to improve overall efficiency.

Purdue Diagram

 

Controlling for Potential Compromise

The core concept of evolving IT/OT systems is interconnectivity. Gone are the days of Level 1 and  2 devices capable only of internal interactions, while those on Levels 3, 4, and 5 connect with networks at large. Bolstered by the adoption of the Industrial Internet of Things (IIoT), continuous connectivity is par for the course.

The challenge? More devices create an expanding attack surface. If attackers can compromise databases or applications, they may be able to move vertically down network levels to attack connected OT devices. Even more worrisome is the fact that since these OT devices have historically been one step removed from internet-facing networks, businesses may not have the tools, technology, or manpower necessary to detect potential vulnerabilities that could pave the way for attacks.

It’s worth noting that these OT vulnerabilities aren’t new — they’ve always existed but were often ignored under the pretense of isolation. Given the lack of outside-facing network access, they often posed minimal risk, but as IIoT becomes standard practice, these vulnerabilities pose very real threats.

And these threats can have far-reaching consequences. Consider two cases: One IT attack and one OT compromise. If IT systems are down, staff can be sent home or assigned other tasks while problems are identified and issues are remediated, but production remains on pace. If OT systems fail, meanwhile, manufacturing operations come to standstill. Lacking visibility into OT inventories makes it more difficult for teams to both discover where compromise occurred and determine the best way to remediate the issue.

As a result, controlling for compromise is the second step of Purdue 2.0. RedSeal makes it possible to see what you’re missing. By pulling in data from hundreds of connected tools and sensors and then importing this data into scan engines — such as Tenable — RedSeal can both identify vulnerabilities and provide context for these weak points. Equipped with data about devices themselves, including manufacturing and vendor information, along with metrics that reflect current performance and behavior, companies are better able to discover vulnerabilities and close critical gaps before attackers can exploit OT operations.

Put simply? Companies can’t defend what they can’t see. This means that while the Purdue diagram remains a critical component of CIM success, after 30 years in business, it needs an update. RedSeal can help companies bring OT functions in line with IT frameworks by discovering all devices on the network, pinpointing potential vulnerabilities, and identifying ways to improve OT security.

InfoSeCon Roundup: OT Top of Mind with Many

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The RedSeal team recently attended the sold-out ISSA Triangle InfoSeCon in Raleigh. It was energizing to see and talk to so many people in person. People were excited to be at in-person events again (as were we!) and we had some great discussions at our booth on how RedSeal can help customers understand their environment and stay one step ahead of threat actors looking to exploit existing vulnerabilities. 

Visibility was a top topic at the booth, but I want to focus this blog on our panel discussion, titled ”OT: Still a Security Blindspot”, which, of course, has visibility as a core need. While I was expecting that this topic would be of interest to quite a few attendees, I was not expecting the great reception we received, nor the number of people that stayed behind to talk to us. We had so many great questions, that we have decided to host a webinar with the same title, where we will share some of the same information, and expand it to address some additional topics based on attendee interest. 

I want to highlight some key points we shared during the session:

We started the session talking about OT networks – what they are, and how they exist across all verticals in some way, shape or form (it is not just manufacturers!).  We did share a life sciences customer example to close the session (think about all of the devices in a hospital connected to the Internet – and what could happen if they were hacked!).

Then we got into the “risk” part of the discussion. We shared how OT networks are targeted via vulnerable devices and highlighted actual consequences from some real-life examples. We focused on the Mirai botnet and potential motives from threat actors:  

  • Botnets can simply to be annoying or attention getting, interrupting business 
  • Ransomware has traditionally been for cash or equivalent, but now can also be for deliberate intentional damage
  • Nation State – with espionage as a goal – to disrupt or compromise organizations or governments

Our panelists from Medigate by Claroty provided their perspective based on discussions with their customers. They explained that for many organizations OT was an afterthought when accessing security risks. The audience appeared to agree with this assessment. Unfortunately, this meant that OT has often been the quickest way to cause serious damage at an organization. They have seen this within the 1500+ hospitals they work with. They shared a couple of examples, which clearly demonstrated what can happen if you have vulnerable OT devices:

  • Turning off the air conditioning at a hospital in Phoenix AZ during the summer shut EVERYTHING down
  • Operating rooms must be kept at very specific temps and humidity levels. A customer in CA whose dedicated O.R. HVAC was impacted ended up losing $1M in revenue PER DAY while it was down

One of the reasons that the security risks for OT devices has not been addressed as well as they should is that OT devices have typically been managed by the Facilities organizations, who do not have the training and expertise needed for this task. We did spend some time talking about who “owns” managing and securing these OT devices. Luckily, there is growing awareness of the need for visibility into both OT and IT devices as part of an overall security strategy, and there are emerging solutions to address this need. 

We also spent time discussing how complex managing OT/IT becomes when companies have distributed sites or complex supply chains. The Medigate panelists shared how some of their Life Sciences customers have sites with different OT network topologies, and some even have a mismatch between the topology of the individual site and its production logic. This means there are usually multiple redundant, unmonitored connections at each site, which provides threat actors with numerous opportunities to penetrate the OT network and, once inside, to move laterally within it. 

This led to a conversation among the panelist on how to address the IT/OT visibility needs:

  1. First step: gain visibility into where OT is and then integrate it with existing IT security infrastructure 
  2. Ongoing: alignment and collaboration between and across IT and OT security, as well as with a range of third-party vendors, technicians, and contractors
  3. End goal: enable all teams (facilities, IT, security, networking, etc.) speak the same language from the same source of truth

The above is just a brief review of some of the topics covered during the panel discussion. If you are interested in hearing more about how to address IT/OT visibility needs and hear about how customers are addressing these needs or find out more about RedSeal, please visit our website or contact us today!