Doesn't look that bad to me. The hard to reach and out of sight areas like that often end up looking like that, unless you are VERY meticulous on cleaning.
I know a guy who cleans his bikes with q-tips. Literally. His daily rider (a DL650) is coming up on 25,000 miles in 9 months, and not a seal on that thing even weeps. It looks like it just came off the showroom floor. May have kept himself out of a big dollar repair on his Duc too when he found some seal leaking just slightly and had a ready-to-fail oil pump replaced. If the bike wasn't immaculate, he'd never have noticed.
He said of my bike, "It looks like you bury it in a hole in the ground at night, and it claws its way out- zombie style- every morning." (This was after two days of riding on wet, salty roads... it's usually not that bad.)
Back to the problem at hand, unless I'm just entirely wrong, even the silver cases are painted, which is why they don't corrode. The sump isn't, so it does.
May have been hit with Simple Green at some point, since people like to use the stuff to clean engines for some reason, even though it's not nice to aluminum. Since the bolts are rusted too, I'd assume that you've just picked up salt from somewhere, and probably didn't meticulously clean the bottom of the bike. It's aluminum, so the oxide coating with protect the rest of the piece.
You could pull the sump, clean it up, and clear it, and it'd probably hold up better. Replace the bolts with some cad-plated ones while you're at it.
Or... y'know... just ride the bike and don't worry about it.
