http://arstechnica.com/security/2013/10 ... -bitcoins/Old reddit thread:
http://www.reddit.com/r/sysadmin/commen ... ptolocker/TLDR: Ransomware is malware that holds your computer hostage. It generally locks up your computer (generally loads pre-OS boot) and demands payment before sending you the unlock password. Generally, ransomware preys on social engineering to goad you into paying the ransom demand (they try to appear "legit" to raise chance of being paid -- e.g you visit porn site, get 'local' law enforcement message saying you broke some indecency/porn law and need to pay a fine).
CryptoLocker is a strain of ransomware that takes it further by encrypting your data aaaaaand whatever data it can get its hands on via your network connection and file access privileges. No social engineering here, it's out in the clear blackmail through and through.
This is devastating to companies that have poor backup practices (no offline backup) and poor access and control architecture/process review
The more you know~! :D