Hello Dolly, is a famous song by Jazz singer Louis Armstrong and a WordPress plugin with the words to his song Hello Dolly. While a plugin like that would usually get few downloads this comes pre-installed in every single WordPress install.
Before you start panicking Hello Dolly is not vulnerable at least not that we are aware of, rather pirates are exploiting vulnerabilities in other plugins you have installed and inserting malware into the plugins directory called WPCoreSys. Hello Dolly is mentioned because they attempt to mask their malware by making database entries claiming it is for the Hello Dolly plugin table. Hello Dolly does not have a database, but most people do not know that.
Programs like anti malware removal have detected and removed WPCoreSYS, unfortunately at that point the damage has already been done and could cost your company tens of thousands of dollars in sales.
WPCoreSYS is a malware infection for WordPress that injects it’s own malicious code into valid themes, plugins and even the wordpress core to try and make it harder to remove.
We have cleaned up WPCoreSys infections, which would be covered under any of our malware removal plans, including our most affordable plan that starts at 49.99.
You can see a whole list of our plans on https://planetzuda.com