Authorities around the world, led by the UK's National Crime Agency (NCA), have banded together to tackle the Shylock banking malware.
Shylock - so called because its code contains excerpts from Shakespeare's Merchant of Venice - has infected at least 30,000 computers running Microsoft Windows worldwide.
The malware - which steals bank login details and transfers money out - has primarily targeted UK-based business and personal accounts, although it is thought that its developers are based elsewhere.
In a UK first, the NCA has been leading an international operation, working with GCHQ, the FBI, Europol and the German Federal Police, as well as security firms BAE Systems Dell SecureWorks and Kaspersky Lab, to disrupt the infrastructure that Shylock relies on.
Authorities have managed to seize servers which form the command and control system for the trojan, as well as take control of the domains it uses for communication between infected computers.
Andy Archibald, deputy director, national cyber crime unit, NCA, says: "This phase of activity is intended to have a significant effect on the Shylock infrastructure, and demonstrates how we are using partnerships across sectors and across national boundaries to cut cyber crime impacting the UK."
The NCA says that people who have their computers set up for automated operating system updates do not need to take any action as the malware will be removed the next time their machines are restarted.