Hackers Circle as Individual Investors Pour Cash Into Crypto

Rosa Maguina plowed a big chunk of her savings into cryptocurrency early this year, joining other individual investors trying to strike while bitcoin was hot. The funds vanished after a hacker hijacked her phone number for just two hours.

Ms. Maguina, who runs an events logistics business with her husband in Doral, Fla., said she was about to go to sleep on July 5 when she noticed her phone lost its signal. By the time Ms. Maguina’s service was restored, she said, an unauthorized user had changed her passwords for trading platforms Binance and


and initiated transactions that emptied her accounts of crypto valued at around $80,000 at the time.

“It was like someone coming through the window or backdoor into your house,” Ms. Maguina said. “You feel that there’s nothing you can do.”

Criminals have a history of stealing money from wealthy or well-known crypto investors through SIM swaps, or switching a phone number from one device’s subscriber identity module to another. But the crypto boom among mom-and-pop investors has led hackers to increasingly circle targets like Ms. Maguina, according to cybersecurity experts, lawyers and law-enforcement officials.

The attacks on small investors have sparked legal battles with cellphone carriers, led customers to change plans and pushed some telecom companies to tweak security measures. Law-enforcement agencies are trying to team up across jurisdictions in response to a broadening pool of potential victims. The Federal Communications Commission is honing rules for wireless carriers aimed at limiting SIM-swap fraud, proposing tighter restrictions on how they switch numbers between devices and carriers.

Some wireless companies say federal rules could…