Oil leak from under oil filter
 

My 07 Nightster hasn't been ridden in a week and I checked on it and pretty much all of the oil has leaked onto my garage floor. Oil was leaking from a plug that is partially screwed in (I see silver colored metal and threading) that is directly under the oil filter. It also has an electrical wire attached that goes to the harness wiring assembly. I just got my bike last week so I'm clueless to motorcycle mechanics. Please see attached photo, what is this? Can I tighten it? If so, how?

Thanks a million

Matt