The National Crime Agency (NCA) claims UK citizens have two weeks to protect themselves from two "distinct" pieces of malware that could end up costing computer users millions of pounds.
GOZeus and CryptoLocker are two pieces of malware the NCA is warning users about. They are designed to work together in order to steal users' money.
For example, the former is usually downloaded and installed when a person clicks on a malicious link or document in an email, and links the recipient's computer to a larger botnet.
It then lays dormant on the user's machine until it's given the opportunity to capture the person's bank details, which are then sent back to the botnet.
If such an opportunity does not arise within a certain period of time, the Cryptolocker element will be activated and will start encrypting the user's files without permission.
Shortly afterwards, the victim will be presented with a popup ordering them to cough up between 200 and 300 to decrypt their files, and in turn providing the cyber criminals with another means of extorting cash from those infected with the malware.
The computer systems of more than 15,000 UK citizens are thought to have been infected by the malware already.
The NCA wants computer users to protect themselves from these pieces of malware immediately by ensuring they have up-to-date security software and operating systems installed, as well as by running regular system scans.
In an alert sent out earlier today, the Agency said recent efforts by the FBI, NCA, Europol and ISPs to clamp down on the distribution of this malware has weakened the botnet.
As a result, UK citizens have been gifted a two-week window of opportunity to get their houses in order, the NCA said, and avoid falling victim to it.
Andy Archibald, deputy director of the NCA's National Cyber Crime Unit, said by taking advantage of this two-week period large numbers of UK citizens can ensure their data won't be held to ransom by cyber criminals.
"Whether you find online security complicated or confusing, or simply haven't thought about keeping your personal or office computer safe for a while, now is the time to take action.
"Our message is simple: update your operating system and make this a regular occurrence, update your security software and use it and, think twice before clicking on links or attachments in unsolicited emails," said Archibald.
