Mobile Number Harvesting

Before a smishing or robocall campaign can be launched, fraudsters need a list of active phone numbers. Mobile number harvesting refers to collecting these numbers through multiple means: scraping publicly visible phone numbers from websites, directories, social-media profiles, and job listings; purchasing datasets from data brokers; extracting numbers from hacked databases; and using autodialing infrastructure to probe ranges of numbers to identify those that are connected and in service.

Harvested numbers are segmented by carrier, country, area code, and demographic indicators when possible, then sold or rented through criminal marketplaces. The market for phone-number lists has expanded significantly alongside the rise of smishing, and lists are regularly updated to remove disconnected numbers and add new ones.

Consumers contribute to harvesting when they post their phone number publicly on social media, fill out online forms that sell data to brokers, or use their mobile number as the primary contact for every service they sign up for. Using a separate number such as a VoIP line for online forms and commercial signups, and restricting who can see your phone number on social platforms, reduces your exposure.