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Just as any building has doors, windows and other openings that need to be secured to prevent unauthorized entry, any network or digital environment has access points and exposures that need to be protected. These potential areas through which an attacker can gain unauthorized access collectively form what the cybersecurity industry commonly refers to as the “attack surface.”
Securing the attack surface is one of the most fundamental, yet often overlooked, aspects of cybersecurity – because it’s deceptively simple. It’s like making sure all your doors are locked each night before you go to bed. That’s pretty easy assuming you don’t have more than a few doors that lead outside. But even the simple example of locking doors can quickly get cumbersome if you think about a large apartment complex – with multiple floors, numerous doors, windows, gates, and possibly multiple entry points like service entrances and loading docks. Here, the scale increases not only the number of potential vulnerabilities but also the complexity of managing them.
In cybersecurity and OT, this concept grows even more complex. Unlike physical buildings where vulnerabilities are tangible, in the digital world, things are not immediately visible. Even if you have eyes on your PLCs, HMIs, RTUs, and other physical OT devices, the cyber attack surface lives within layers of software, firmware, communications and connections. With this added scale and complexity, a more comprehensive and vigilant approach becomes crucial.
The cyber attack surface refers to the sum of all the various points where someone can gain unauthorized access, including vulnerabilities within a system or network (known and unknown), as well as all accessible entry points into the system and any network-accessible services.
How do you begin to understand your OT attack surface?
It can be challenging to ascertain the full breadth of your attack surface, which is why implementing Attack Surface Management (ASM) is so important. Managing the attack surface is fundamental to preventing, detecting, and mitigating most common cyber threats. This process involves key security hardening basics, starting with Asset Inventory – everything starts with knowing what you have, both from a hardware and software perspective. If you don’t know what you have, you can’t fully understand your attack surface. Once you have this information, you can identify security weaknesses and potential entry points that make up your attack surface, such as misconfigurations, open ports and services, vulnerabilities, and connections. Digital attack surfaces cover everything from weak passwords, the network perimeter (including internet-facing servers, routers, and firewalls which unauthorized users can attempt to breach), to web applications and software. Physical attack surfaces exist wherever there are tangible assets too, such as computers, servers, and IoT devices. These attack surfaces are mostly breached through either physical infrastructure (such as data centers or server rooms), or through device theft. USBs can also be used to insert malware or steal data.
How can you work to reduce your OT attack surface?
Once you have a clear understanding of your attack surface, you can begin working to reduce it. This involves continuous monitoring of OT assets and keeping your inventory up-to-date to reflect changes in real-time. Regular assessments are crucial for ensuring secure configurations and for identifying new and emerging vulnerabilities. Staying informed about outdated software and managing configurations, such as open ports and services, are essential practices.
Continuous monitoring is vital because it alerts you to any changes that could indicate potential security threats. For example, a change in configuration such as escalated account privileges could signal malicious behavior, possibly serving as a precursor to lateral movement through the network. You can effectively manage and minimize your attack surface by staying vigilant and proactive, successfully enhancing your overall security posture as a result.
Potential attack surface issues to address:
Why is securing OT different than IT?
Managing and securing the attack surface in OT environments presents unique challenges that are not as prevalent in traditional IT settings. In IT, extensive scanning can be deployed without significant risk to system stability. However, due to the critical nature and operational characteristics of OT devices, such approaches are not suitable in OT environments. Scanning OT systems as one would in an IT network can risk disrupting the devices, potentially leading to operational downtime. OT devices often operate continuously and are sensitive to changes, making typical IT security assessments too intrusive.
Given these complexities, OT-specific approaches are necessary—methods that are both safe and effective in gathering essential asset data without compromising operational integrity.
How can Industrial Defender and OT asset management help harden your attack surface?
Like much of cybersecurity, effectively reducing an attack surface is a continuous process that requires constant upkeep and maintenance. By gaining a deeper understanding of your system's full attack surface, you are already taking the first step towards successful security. It can be particularly challenging to gain insight into OT threats, however this is what makes attack surface management so imperative.
Industrial Defender has been at the forefront of implementing such approaches since 2006, drawing on decades of experience in highly critical environments, such as electric utilities. Our expertise in monitoring and managing the OT attack surface considers the unique requirements of these critical operating systems, delivering comprehensive, deep, and accurate OT asset data -- through OT asset management. We can help you not only identify assets and their security weaknesses but also assess the level of risk and potential impact on your operations, ensuring ongoing availability, reliability, and resilience.
While attack surface management might appear formidable at first glance, especially in OT environments, having the right partners and the right approach makes all the difference. With Industrial Defender, it becomes a practical and effective security measure to mitigate threats and enhance the availability and resilience of your operations.
To learn more, read about managing your OT environment with Industrial Defender below.
