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. The campaign is called "SubdoMailing, as the threat actors hijack abandoned subdomains and domains belonging to well-known companies to send their malicious emails.
Read the article: BleepingComputer