WASHINGTON: Cybersecurity investigators noticed a highly unusual software crash — it was affecting a small number of smartphones belonging to people who worked in government, politics, tech and journalism. The crashes, which began late last year and carried into 2025, were the tipoff to a sophisticated cyberattack that may have allowed hackers to infiltrate a phone without a single click from the user.

Foreign hackers have increasingly identified smartphones, other mobile devices and the apps they use as a weak link in U.S. cyberdefenses.

WASHINGTON: Cybersecurity investigators noticed a highly unusual software crash — it was affecting a small number of smartphones belonging to people who worked in government,…