The request on your log is made by a malicious program scanning the net for vulnerable servers (that is, misconfigured or bugged software).
Current HFS version has no known vulnerabilities, that means that there's no actual risk. You was "tested", but with no effect.
Your HFS is currently open to anyone.
That's not a problem while you don't have stuff that you want it to be available to anyone.
@foggy: yes, AFAIK