The host at this IP address is running a malware botnet controller which is being used to control infected computers (bots) around the globe using a trojan horse.
Malware botnet controller at 185.251.91.152 on port 443.
$ telnet 185.251.91.152 443
Trying 185.251.91.152…
Connected to 185.251.91.152.
Escape character is ‘^]’
Malicious domains observed at this IP address:
bomjan05.top. 600 IN A 185.251.91.152
morege04.top. 600 IN A 185.251.91.152
morlum03.top. 600 IN A 185.251.91.152