On 19 March, the company filed a court action using the US Racketeer Influenced and Corrupt Organizations (RICO) Act alleging that 39 individuals - "John Does 1-39" - were responsible for Zeus-based botnets that had stolen an alleged $100 million (£63 million) over the past five years by after infecting 13 million PCs.

By 23 March, the company's Digital Crimes Unit, the Information Sharing and Analysis Center (FS-ISAC) and the Electronic Payments Association NACHA, launched 'Operation b71', physically seizing hosted servers allegedly used as command and control for the bots, gathering further evidence against the accused.

"We don't expect this action to have wiped out every Zeus botnet operating in the world. However, together, we have proactively disrupted some of the most harmful botnets, and we expect this effort will significantly impact the cybercriminal underground for quite some time," said Microsoft in an .

In addition to Zeus, botnets built using the related SpyEye and Ice-IX variants were also disrupted, Microsoft said.

The action is only the latest in a long line stretching back years that have seen Microsoft and its Digital Crimes Unit become perhaps the most successful anti-cybercrime organisation on the planet, harnessing local laws, trade bodies and the security industry itself to counter a digital crimewave.