The hackers had deployed malicious software, or malware, that let them take over the plant’s safety instrumented systems. These physical controllers and their associated software are the last line of defense against life-threatening disasters. They are supposed to kick in if they detect dangerous conditions, returning processes to safe levels or shutting them down altogether by triggering things like shutoff valves and pressure-release mechanisms.
How dangerous it is?
The malware made it possible to take over these industrial systems remotely. Had the intruders disabled or tampered with them, and then used other software to make equipment at the plant malfunction, the consequences could have been catastrophic. Fortunately, a flaw in the code gave the hackers away before they could do any harm.
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