The National Crime Agency (NCA) has issued a warning alerting people to a mass 'ransomware' spam email.
The email - which appears to be particularly targeted at mall and medium businesses - has a legitimate looking attachment from a bank or financial institution.
It purports to inform about an invoice, suspicious bank payment of fax for example but is in fact a malware that can install Cryptolocker – which is a piece of ransomware.
If opened the malware encrypts the user's files as well as that of the local network it is connected to.
Once encrypted, the computer will display a splash screen with a count down timer and a demand for the payment of 2 Bitcoins in ransom (Approx £536 as at 15/11/2013) for the decryption key.
Lee Miles, Deputy Head of the NCCU says "The NCA are actively pursuing organised crime groups committing this type of crime. We are working in cooperation with industry and international partners to identify and bring to justice those responsible and reduce the risk to the public."
The NCA stresses it would never recommend paying a ransom as there is no guarantee it would be honoured.
If you computer is infected it should be reported to Action Fraud immediately.
For further advice on staying safe online see GetSafeOnline.