I upgraded from 2.3.1 to 2.3.2 and I noticed my website was hanging found that one of my post had the iframe connection to 61.132.75.71
I’m not sure if this happened before or after the upgrade.
Also, I installed a new theme, and I was going to make some changes to the code, and noticed some strange code in it. Thats when I started looking around to see any sneaky code was in the theme. I was right, that certain line of code was in the sidebar, header, footer and so on. After getting the sneaky code out of my theme. I noticed my website kept hanging, I thought I still had some bad code, when I did a search on the ip it was trying to connect to, I found th is thread about the iframe. Sure enough it was in a post about spyware I wrote some time ago.