Spammers behind a pill scam campaign are trying a new technique, betting on unconventional representation of URLs in spam messages to keep them undetected by email protection systems and URL blocklists. Spammers combined convincing messages with IP addresses encoded in the hexadecimal numeral system that lead to fake pharma sites after a few redirects. The purpose of the operation is to convince recipients to buy fake drugs, sugar pills, snake oil products, and items of doubtful quality. The peak recorded close to 25,000 emails going to inboxes across the world.
Source: https://www.bleepingcomputer.com/news/security/drug-spammers-start-using-new-technique-to-bypass-spam-filters/