The FBI in the US was successful in disrupting a hacking network, making security updates by users around the world more effective, National Crime Agency officials said.
The NCA is working closely with the FBI in order to minimise the impact of the attack.
“Those committing cyber crime impacting the UK are often highly-skilled and operating from abroad,” Andy Archibald from the NCA's National Cyber Crime Unit said.
Computer users are constantly being told to change passwords and update software due to the latest "Trojan" or "Bot" - but what are they?
The malware, called GOZeuS is hiding within email attachments, and once downloaded will enable hackers to mine infected computers.