Popular AdSense advertisements of Google have been hijacked to advertise pornography and gambling sites. It is said that the malware intrudes to user’s PC through a website and then generates a fake ads in place of the real ones. The fake ads are hard to distinguish from the original ones, but they all promote sites with improper content. As advertising of gambling and adult sites are prohibited on AdSense, the fact alone should put you on guard. Google said that the problem is carefully investigated, but the other threats this Trojan can possibly pose remain yet unknown.