A massive ad fraud campaign named "SubdoMailing" is using over 8,000 legitimate internet domains and 13,000 subdomains to send up to five million emails per day to generate revenue through scams and malvertising.

“SubdoMailing” is a fraud campaign that uses over 8,000 domains and 13,000 subdomains to send 5 million daily emails with scams. Attackers bypass spam filters using domains from well-known companies, such as MSN, VMware, and eBay. Discovered by Guardio Labs in 2022, the campaign exploits SPF and DKIM email policies.