A scan of internet-connected industrial equipment found 4,400 exposed PLCs, including 22 in cities recently targeted by water system attacks.

ForeScout said one of them warranted rating at the maximum severity level, although DrayTek has issued patches.

Cyber MDX is known for its research into potential cyberthreats against connected health care devices like patient monitors and infusion pumps.

Who's watching the watchers?

At least 150 vendors are affected, but Forescout said it's hard to know for sure how many more.

Over time, the hope is that we can start building connected devices with a security-first approach.

Advent International will purchase outstanding Forescout shares for $29 apiece.

The discovery highlights how obscure companies can have an outsize impact on supply chain security.

Advent International now is negotiating an "alternative" deal, the firm says.

The deal is expected to close in the second quarter of this year.