Microsoft announced legal action Monday seeking to disrupt a major cybercrime digital network that uses more than 1 million zombie computers to loot bank accounts and spread ransomware, which experts consider a major threat to the U.S. presidential election.

The operation to knock offline command-and-control servers for a global botnet that uses an infrastructure known as Trickbot to infect computers with malware was initiated with an order that Microsoft obtained in Virginia federal court on Oct. 6. Microsoft argued that the crime network is abusing its trademark.

“It is very hard to tell how effective it will be but we are confident it will have a very long-lasting effect,” said Jean-Ian Boutin, head of threat research at ESET, one of several cybersecurity firms that partnered with Microsoft to map the command-and-control servers. “We’re sure that they are going to notice and it will be hard for them to get back to the state that the botnet was in.”