No need for a blacklist either, I don't believe there's been a single example of a malware using a purely DNS based C&C (e.g by utilizing TXT records) instead o

No need for a blacklist either, I don't believe there's been a single example of a malware using a purely DNS based C&C (e.g by utilizing TXT records) instead of using DNS to get the IP address for the C&C server. Of course there's always an exception, in this case there exists DNS beacons included in pentesting suite Cobalt Strike, but that doesn't seem to be something widely used.