That's a 74% rise in one year, according to the latest Microsoft Digital Defense Report.
But many people still rely on passwords, and don't even use the two-factor authentication now considered critical.
"As long as passwords are still part of the equation, they're vulnerable," Joy Chik, Microsoft's vice president of identity, wrote in a September 2021 company blog post.
Based on a sample of more than 39 million IoT and OT devices, about 20% used identical usernames and passwords, according to the Microsoft report.
Even if a provider doesn't require it to be used, multi-factor authentication is a valuable security tool that's underutilized, according to security professionals.