Security Researchers from Spider.io have discovered a new Botnet named as "Chameleon Botnet" that steals millions of dollars from advertisers by generating fake ad clicks.

The Spider.io claims the "Chameleon" botnet operates from 120,000 infected host machines - 95% of these affected PCs are using US-based IP addresses.

The firm has observed the botnets targeting at least 202 websites, hitting them with 9 billion ad impressions.

"Each bot often masquerades as several concurrent website visitors, each visiting multiple pages across multiple websites." The report reads.