SPOTLIGHT Cybersecurity
Is your facility connected? You are then at risk
IoT-enabled devices used in industrial applications are vulnerable to many forms of cyberattack. Michael Barrett, Managing Director of Nexus Industrial Memory, outlines some ways in which devices might be attacked and suggests how to make them more secure
[Image: Lalit Kumar for Unsplash] S
ecurity is a growing concern for the IoT and its industrial counterpart, the IIoT. It’s worth mentioning that those attacking
IIoT have diff erent objectives to those attacking IoT. For instance, IIoT data theft is more likely to be about acquiring industrially-sensitive information, and ransomware attacks will be out to disable equipment and disrupt processes. Other attacks aim to cause damage by compromising safety-critical systems. If a device is connected to the Internet, it is exposed to cyberattacks, and if it still uses the default username and password with which it left the factory, it may as well have no security at all. For example, Mirai, a self-propagating botnet (a.k.a., “zombie”) attacks poorly-protected systems using telnet to fi nd devices that are still using their default username and password.
If these devices are used in multiple locations around the world – to report performance and diagnostic data back to a single server, for example – they can be instructed (from a command-and-control, CnC, centre) to perform a distributed denial of service (DDoS) attack (Figure 1).
8 November 2021 | Automation Varied attacks
In many cases though, it is not necessary to rely on the user failing to change a default password. There’s another way in: through data the device is expecting to receive. For instance, a common form of attack on IoT-enabled devices, and for which the programs are written in a low- level language like C, is through a forced memory-buff er overfl ow. The spearhead of the attack is to write data to memory reserved for runtime activities that is larger than that the device expects to receive. The excess data overfl ows into other memory space and overwrites machine code that governs the system’s behaviour. If the overfl ow data is something like a new return address, a diff erent part of the program will execute next. This might be a legitimate function, such as the restoration of factory settings (including default passwords), or the hacker can simply set a new password. Either way, the hacker has access to the system. However, the legitimate user might wonder why they no longer have access. A more severe memory buff er overfl ow attack sees the introduction of shellcode
to give the device new behaviour. This might be to reveal the password set by the legitimate user of the system, or it could be to reveal the password the device uses to get on to the network and communicate with other devices. The legitimate user may never know the device has been compromised. As for how the hacker knows where to write the overfl ow data and what it should be, if the device is an off -the-shelf product, it can be reverse- engineered to establish its memory map.
Protection One way of protecting against memory- buff er overfl ow attacks is not to program in a low-level language. Instead, use C# or Java, for example. Also, if there’s room for an operating system use it since it will off er memory management. If not, dedicated memory management unit (MMU) chips can be used. Either way, certain areas of the device’s memory need to be protected (declared as Read Only, for example) during runtime.
An IIoT device can also be attacked
through its application program interface (API). Many devices use a representational state transfer (REST)-based API called
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