Malaware

I installed the POPUP today and it was not working, I desactivated the plugin and I receive a message from my hosting that it had a malware. I ended up getting locked out of my WP directory and dashboard because of it. I uninstalled the plugin and removed the BLOCK CONTENT with error message on the page the CODE was inserted. Problem solve. Please verify why it send the following MALWARE message.

{HEX}Malware.Expert.generic.eval.21