Microsoft Turns to Old Enemy Linux to Solve Vexing Tech Threat

The software will be embedded in chips for toys, household appliances, industrial machinery and millions of other internet-connected devices

To head off cyberattacks like the one in 2016 that took down Twitter Inc. and Netflix Inc., Microsoft Corp. is deploying widely used operating-system software it bolstered with enhanced security features.

It won’t, however, be Windows.

Microsoft instead plans to embed Linux, a rival technology former Chief Executive Steve Ballmer once called...