A recent trend in malware has been to infect your system and “hold it ransom” by denying you access to your files until you pay for a service or fix.
Per a recent article by Herb Weisbaum for NBC News: “Imagine having all of your computer files — including taxes and other important data — kidnapped and held for ransom. It’s happening more and more. Internet criminals are now targeting U.S.computers with online extortion attacks. Ransomware is not new, but the latest version — named Reveton — is more sophisticated than most of this malicious software. The Reveton Trojan instantly locks the infected computer. Then it displays a message on the screen that looks like it’s from the FBI. The bogus message says the user violated federal law by downloading child pornography or illegally using or distributing copyrighted music or video. To unlock the machine, the user is told to pay a fine via a prepaid money card, online payment service or wire transfer.”
Infections like these are usually carried out by “drive-by” downloads. A “drive-by” download is when you visit a normal webpage that might have an infected advertisement or set of links/graphics. Although you are not actively visiting a bad website, the compromised ad or image can download to your system and use exploits to attempt to run malicious code. The best way to prevent becoming a victim is by employing a two-fold strategy. First, have updated anti-virus software loaded on your computer. And second, use a website filter such as our ESG Internet Filtering which checks each website you visit against a real-time list of compromised sites/advertisers/hosting providers. Working in tandem, these dual tools can largely prevent your system from downloading the attacking code and/or neutralizing it before it can exploit a vulnerability.
You can read the full article here: http://bottomline.nbcnews.com/_news/2012/08/29/13530504-latest-ransomware-attacks-are-scarily-sophisticated?lite