Hackers were able to manipulate the webpage of an Indian anti-virus maker and using an invisible iframe redirect visitors to a page that would install malicious code on visitor's computers.
The report makes a point of noting that the Indian company also did business helping people recover data after an attack. (Are they trying to hint something?)
According to a PCWorld.com report at Yahoo.com "Hacked Antivirus Site Delivers a Virus "
McAfee Security Research Manager Dave Marcus believes that the site was compromised by exploiting a Web programming error, most likely in the site's SQL or PHP code. Security experts say that criminals have written automated programs that scour the Web for these types of flaws and then automatically infect sites, making this an increasingly common problem.
And if you aren't scared enough yet, then look at the side bar there for the link to the PC World article "Malware Evolving Too Fast for Antivirus Apps" (Well the link copied over so I'll just leave it here too). That article says that up to date malware (I suppose they mean virus, trojans, and spyware) blockers can catch only 1/4 of malware and a special site created to help the internet safety industry is actually helping commercial malware creators get around them.
Malware is big business now.