Feature: Industrial electronics
There are mixed views whether the Purdue model must be replaced or enhanced, in light of the increased use of IIoT within the manufacturing zone
Ways in Any device connected to the Internet is open to cyber attacks. If it still uses its factory-fitted usernames and passwords, 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 find devices using their default settings. If these devices are across multiple locations, the botnet then instructs them to perform a distributed denial of service (DDoS) attack against their server. In many cases, however, there’s no need to use these settings, since
there’s another entry point – through data transmitted to the device. One common attack is through a forced memory-buffer overflow. Hackers may know where to send the overflow data for off-the-shelf devices, since they can easily reverse-engineer them to establish their memory map. Te malicious programme writes data to the device’s memory
Protecting IIoT devices from cyber attacks
By Michael Barrett, Managing Director, Nexus Industrial Memory
I
ndustrial IoT (IIoT) is at the heart of Industry 4.0, facilitating easy connectivity to harness and interpret data, which in turn helps manufacturers tailor their predictive-maintenance programmes for greater efficiency. However, with so many systems and devices being part
of different networks, security is becoming a growing concern. Tere are various motivations for cyber attacks; some focus on data theſt (to acquire competitively-sensitive information), and others cause damage by disabling equipment and halting industrial processes.
32 December 2021/January 2022
www.electronicsworld.co.uk
reserved for runtime activities. It sends more data than the device expects to receive (Figure 1), so the excess overflows into other memory space, to overwrite the machine code that governs the system’s behaviour. If the overflow data is something like a new return address, a different part of the program will execute next. Tis 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 gains access to the system and the legitimate user is denied access. A more severe attack involves a shellcode that alters the device’s
behaviour. Tis might be to reveal the password set by the system’s legitimate user, or to reveal a device’s password to access the local network and communicate with other devices. Most of the time the legitimate users have no idea the device has been compromised.
Adding protection Typically, for IoT devices programs are written in a low-level language like C. So, an obvious way to start protecting them against buffer overflow attacks is to program them with C# or Java, for example. In addition, use an operating system for memory management or a dedicated memory management unit (MMU) to protect certain areas of the device’s memory (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 RESTful. Such APIs are popular since they do not require much bandwidth, can be craſted in Python
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