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 15.235.13.122 on port 3000 TCP:
$ telnet 15.235.13.122 3000
Trying 15.235.13.122…
Connected to 15.235.13.122.
Escape character is ‘^]’
$ nslookup 15.235.13.122
ns5009176.ip-15-235-13.net
Referencing malware samples (MD5 hash):
e82471b292f43026097991b562a2ce29 — AV detection: 52 / 67 (77.61%)