I have previously written about the dangers of ransomeware, where your computer is encrypted and you have to pay to unlock it, and other forms of hacking. RadioLab recently broadcast a Podcast on this topic. It is very interesting and informative, and if it weren’t real, a good suspenseful story. I encourage you to listen. The episode is titled Darkode.
There are ways to protect yourself. First, this is mostly a Windows issue so make sure your anti-virus software is up to date and install all the updates to your OS.
Second, most likely, these attacks do not affect external drives, though they could. At a minimum make sure you are setup for regular backups. An additional precaution would be to have a cloud-based backup like Mozy or Crashplan, and/or have an external backup that you unplug from your computer. By taking these precautions, if you are attacked, you can wipe your computer clean and reinstall the backup thus avoiding the payment of the ransom.
If you own a Mac you are not entirely immune. There is fake ransomware that attacks Macs. This is malware that displays a ransom message but does not encrypt your files, all your data is still there. There are tricks to deleting the malware.
If something like this should happen to you, don’t panic, call me or another professional to explore your options.