Thom Brown shares some advice:
As you may have heard, there are reportedly over 1,500 PostgreSQL servers that have been exploited to mine Bitcoin. And your server could be next if you haven’t taken precautions. Firstly, you need to update to the latest minor release, just so no known exploitable bugs exist on your system. But regardless of whether you update, your PostgreSQL instance could still be misconfigured in a way that would allow unwelcome visitors access, so you need to make sure you shore up your defenses. Here are some steps you should take.
Click through for some solid guidance.