Cryptolocker is ransomware, software which holds your files to ransom.
The software is usually spread through infected attachments to emails. Once a computer is infected, it begins encrypting files on the infected computer and the attached network. Once all the files are encrypted, it posts a message asking for payment to decrypt the files and threatens to destroy the information if it doesn't get paid. The payments are made by untraceable Weston Union transfer.
That means you'll have to rely on any backups of your data to get it back but in most case the backups also get encrypted. So there is no real option left to but to pay.
The computers that control cryptolocker on the Internet are being shutdown but it is a game of “whack-a-mole” as one gets shutdown, another one pops up. Which leads to the second problem, if the computer that has encrypted your system is shutdown then the criminals may not be able to return the data, even if the ransom has been paid.
So please follow these steps to help prevent this problem:
- Do not open attachments that you are not expecting even if they appear to be from a legitimate source.
- Ensure that Windows updates are applied.
- Run good anti-virus software
- Consider moving more data to cloud services offered by Google and others.
- Use a cloud backup service such as Carbonite or Mozy