The host at this IP address is obviously operated by cybercriminals. It 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 located at 18.104.22.168 on port 3543 TCP:
$ telnet 22.214.171.124 3543
Connected to 126.96.36.199.
Escape character is ‘^]’
$ dig +short apostle28.duckdns.org
Referencing malware samples (MD5 hash):
e5df17e52c9ad8157ef9ad8c42072f6e — AV detection: 18 / 58 (31.03%)