While automated attacks by a networked army of computers aren't a new problem, the methods that botnets are using are getting more complex.
They're also increasing in number with the latest cybercrime report from ThreatMetrix suggesting that the number of attacks between January and March this year is up by over a third, compared with just the previous quarter. The report states that 311 million bot attacks were detected and stopped by its technology in the opening three months of 2016.
Botnet attacks used to just be large volume distributed denial of service (DDoS) or spam attacks, designed to overwhelm servers to the point of collapse or act as a distraction in order to allow cybercriminals to hack into the targeted system without being detected.
Now however, the cybersecurity researchers say that botnets are being used in a new way - to test stolen login details in a way which allows them to evade detection by security systems.