More than 60 percent of malicious advertisements setup with fraudulent details would have been easily avoidable had proper vetting been conducted, an advocacy group says,
Websites had failed to run proper checks and “operational discipline", leading to the increasing proliferation of the scam sites.
The scam allowed criminals to foist malware on visitors of genuine websites by setting up compromised ads run through fake identities, and contact details.
An average of 10 billion malicious advertisements were seen in 2012 with 42 percent delivered as drive-by executions without user interaction, according to the Online Trust Alliance (OTA).
Executive director Craig Spiezle said scores of people could be exposed before ads were taken down.
“If that ad gets served, even if it is taken down 24 to 48 hours later, hundreds of thousands have seen it, Spiezle said.
He said websites should understand the activities and reputation of advertisers and the urgency of the ad placement.