CryptoLocker From Wikipedia, the free encyclopedia

CryptoLocker is malware that surfaced in late 2013. A form of ransomware targeting Microsoft Windows-based computers, the trojan encrypts files stored on local hard drives and mounted network drives using public-key cryptography, and then displays a message saying that the files will be decrypted if a fee is paid through an anonymous payment service by a specified deadline, beyond which decryption is no longer possible.

Contents Operation CryptoLocker typically propagates as an attachment to a seemingly innocuous e-mail (usually taking the appearance of a legitimate company e-mail), or from a botnet. The attached ZIP file contains an executable file with filename and icon disguised as a PDF file, taking advantage of Windows' default behaviour of hiding the extension from file names to disguise the real .EXE extension. Some instances may actually contain the Zeus trojan instead, which in turn installs CryptoLocker.

Read more: http://en.wikipedia.org/wiki/CryptoLocker