Hackers Roil Entire Industries With Attacks on IT Supply Chain

Across Paraguay, hackers knocked out online services provided by the foreign ministry and companies. In Sweden, they crippled the payroll and human resources systems of more than 100 government bodies, including the central bank and parliament, as well as hospitals, retailers and others.

In the US, intruders took down a software system that the biggest banks use to process trades, and they crippled a network that connects medical providers and pharmacies with insurance companies. Those attacks, against EquiLend and UnitedHealth Group Inc.’s Change Healthcare division, wreaked havoc on Wall Street and the American health-care system.

These incidents all occurred ...