How Spam Callers Get Your Phone Number

Tech outlet Engadget has outlined how spam callers and text senders get hold of people's phone numbers and how to protect yours. The guide is aimed mainly at US readers, as it refers to the Do Not Call Registry run by the Federal Trade Commission (FTC), where people can sign up to restrict telemarketing calls.

Where the numbers come from

Part of the unwanted traffic is simply bad luck. A person may give their number for an important account, only for that site or service to suffer a data breach. Illegal robocallers may also dial numbers at random or take them from public records such as court directories, property deeds and corporate filings.

Most of the numbers in spammers' and scammers' hands, however, are bought from data brokers. Often the data is legally resold to third parties after someone signs up for an account, loyalty program, contest or sweepstakes. Consent is typically given as a mandatory condition of using a service, or while hurrying through web pages with deliberately confusing checkboxes.

Numbers can also be harvested through phishing: filling in a fake login page, creating an account on a sketchy website, applying for a fake job listing or signing up for a bogus app. If anything has been registered with your phone number, the article says, there is a strong likelihood the information has been sold.

Protecting your number

Devices offer some protection against phishing, such as browser warnings about risky sites and Android's enhanced protection against bank scams. The guide also advises avoiding unfamiliar sites or ones crammed with ads, and searching for reviews and scam reports before signing up. Numbers should be hidden on public profiles, and people should be mindful of how many accounts they create and which boxes they tick.

The FTC registry limits most telemarketing calls but does not stop exempt callers: charities, political parties, debt collectors and telephone surveyors. To find out how a number may have leaked, you can search your email address on Have I Been Pwned, a site that shows data breaches, or google the number in quotation marks.