Two major online ad networks DoubleClick and MSN were serving malware via drive-by download exploits over the last week, experts say. Attackers impersonated an online advertising provider by impersonating ADShuffle.com. The ads used various exploits to install malware on victims PCs. The episode shows how difficult the problem can be to address, but the episode shows just how difficult it is to address. A spokesman for Google, which owns DoubleClick, told the IDG News Service that the malicious ads were only being served for a short time.
Source: https://threatpost.com/major-ad-networks-found-serving-malicious-ads-121210/74765/