Google has been attacked again and this time it’s a botnet called Koobface. An internet security firm, Trend Micro Security Advisory, headquartered in Tokyo discovered the attack on Thursday morning. It spammed thousands of reader addresses.

Koobface is a botnet, a network of computer systems that have been compromised without the owner’s knowledge. It is a kind of malware that exploits the social networking aspects of websites. Spread through social networks, it is known as revolutionary botnet in the world of cyber crime.

The attack works when a Google Account controlled by the Koobface hosts a page with a fake YouTube video. When a victim clicks on the fake video, the user is directed to a compromised website which hosts another fake YouTube video. The compromised website leads to user’s infection, with the subsequent result of the victim becoming part of the Koobface botnet.