Sophos also reports, from a tip that they received, that Facebook also served a number of malicious ads:
Naked Security reader John sent us a tip that there were malicious ads circulating on Facebook.
When you click on the ad on Facebook, you are redirected to a page saying you need to install Adobe Flash Player. The malware is served up when you click and is called AdobeFlashPlayer.exe.
Malvertising attacks like this have been a growing concern. According to Web security firm Dasient, in the last three months of 2010 attackers managed to serve more than 3 million malvertising impressions every day.
Also, a few weeks ago, malicious and bogus anti-virus selling software ads somehow made it on to the ad network that is used by the London Stock Exchange and Autotrader, as reported by the BBC:
Tens of thousands of people could have been caught out by cyber criminals who put booby-trapped adverts on popular webpages.
The criminals racked up the victims by compromising the computers used by ad firm Unanimis to display adverts to popular websites.
The ads appeared on the websites of the London Stock Exchange, Autotrader, the Vue cinema chain and six other sites.
Unanimis said it moved quickly to pull the adverts once they were discovered.
More information about the plague of malvertising can be found at the website of the Online Trust Alliance.
For my security and technology observations throughout the day, find me on Twitter at @georgevhulme.