CryptoDefense represents a serious threat.
This ransomware targets text, pictures, video, PDF and Office files and encrypts these with a strong RSA-2048 key which is hard (closer to impossible) to undo. It also wipes out Shadow Copies which are used by many backup programs. This gives it the potential to cause major, major problems.
The cybercriminals behind CryptoDefense charge $500 in BitCoins to unlock the system, increased to $1,000 if you fail to pay up within the first four days.
In its earliest versions, the malware was installed through programs that pretended to be flash updates or video players needed to view online footage. It has since moved on to a variety of different phishing attacks in the form of emails with a zip file directing recipients to “open the attached document” which was supposed to have been “scanned and sent to you”.
Please be careful with any and all updates and attachments of any sort. It does not matter what type of virus protection you have, you need to be careful or pay an expensive price of downtime or data-loss.