A malvertising attack targeted TweetMeme users after a rogue advertiser made its way onto the website. The malicious advertisements directed user to third party websites displaying fake malware alerts with the purpose of convincing users to install scareware.

Malvertising (malicious advertising) is a type of attack where cyber crooks manage to insert rogue ads that lead users to malicious content . The practice is commonly employed by scareware pushers to distribute their fake antivirus products.

TweetMeme users were targeted via malicious advertisements served by a rogue advertiser at y5-media.com. An investigation of the incident revealed that the threat distributed through these malvertisements was a fake antivirus called Security Threat Analysis.

The researchers explain that requests to y5-media.com bounce through two other websites before landing on the scareware domains. In order to fly under the radar the cyber crooks tried to make the attack as subtle as possible.

Malvertisements can be very dangerous, because unlike black hat search optimization campaigns that poison search results with malicious links, they can are a lot harder to detect, and abuse the trust that users put into legit websites. Popular websites that were previously affected by similar attacks include the New York Times, Gizmodo or Digital Spy.

Ref: http://news.softpedia.com/news/TweetMeme-Hit-by-Malvertisement-147762.shtml