We are given a domain 646f776e756e646572.xyz and asked to find the phone number of the individual who registered it in the format DUCTF{+61<number>}.
Visiting the domain itself will not return any useful information. Instead, the solution is hinted at in the name "Who goes there?".
Performing a whois lookup of the domain 646f776e756e646572.xyz will return full registrar data for Isa Haxmoore, including name, address, and phone number: +61.420091337.
Depending on your chosen formatting you may end up with one of the following two flags:
- DUCTF{+61420091337}
- DUCTF{+61.420091337}