user postgres launches process that takes all CPUs 100% usage

Question

User postgres is running a process that take all CPUs at 100% usage in a centos machine, the postgresql service is not running so it cannot be a query.

When I try to

Answer 1

Congratulations!

By exposing a database with a weak superuser password to the internet you invited somebody to break in and use your CPU for their own purposes, probably mining crypto-currencies.

Take the machine from the internet, wipe it clean and re-install the operating system.