CryptoLocker is a ransomware malware virus that is downloaded via email phishing scams. The emails seem to be coming from phony businesses, as well as fake UPS and FedEx tracking notices. It has also been documented that some victims saw the malware appear following after a previous infection from one or several botnets frequently leveraged in the cyber-criminal underground.
The malware tagets Windows 8, Windows 7, Vista, and XP operating systems.
The malware is capable of locating share drives and other mapped network drives, which allows it to replicate across the network and infect other hosts on the network. It then proceeds to encrypt the victim's files using asymmetric encryption, and demands payment before giving the private decryption key to the victim. Some people have reported that even when they paid the ransom, they did not receive the private key from the hackers.
The easiest way to get rid of the virus is to reformat and hope that there is a back from before the malware was downloaded. I have also heard some news that some people have been able to decrypt the files by finding the private key hidden withing the file system.