What is a hacker to do? The general computer using population is becoming more educated about security, and modern browsers are taking the bite out of phishing scams. Why not kill 2 birds with one stone and find a way to infect legitimate sites?
That is exactly what hackers are now doing, with alarming success. Thus far estimates range from the high 200 thousands to half a million infected websites, most of which seem to be legitimate:
"On Wednesday, several security companies, including San Diego-based Websense Inc., said large numbers of legitimate sites, including ones with URLs belong to the U.N., had been hacked and were serving up malware. Those latest compromises were only the most recent SQL injection attacks, however. Similar attacks have been launched since the first of the year and were last detected in large numbers in March."
The recent rash of malware infestations may be a result of Microsoft’s April 17th posting about a IIS security flaw.
There may not be a perfect solution to this current crisis, but you can never go wrong keeping all your anti-malware measures up to date.