Fix/Move Ethernet on Side of House
Stated another way, your options are to make the best use possible of the cable that's already installed or install new cable that suits your need better.

Ethernet outdoors

There exist environmentally hardened Ethernet switches designed for outdoor use, but you won't find them on the shelf at the local big box electronics store and they'll cost more than consumer/SOHO indoor-rated gear. Then again, indoor-rated gear might perform acceptably for you even outdoors. So there's one option: install an Ethernet switch near enough to all those cables outdoors so that they can be patched into the switch. You'd have to get power to it from somewhere and it would require some kind of protection from water.

Turn cables indoors

Think about what's on the interior side of the wall from that outdoor junction box. Would it be acceptable to place a patch panel near that location? You could cut an opening in the interior wall, pull all the cables from the junction box into a new box inside, and repair the wall.

Modify, abandon, or replace

If all else fails you'll have to install some new cable. Some of the existing cable might run through accessible areas like the attic. Any existing cable you can find and re-route to the new patch panel location saves work in fishing new wire through walls. Consider whether it's useful to have more than one patch (and switch) location to so that everything doesn't have to home-run to a single place.

Don't go to great pains to rip out wire you're not using -- if it isn't hurting anything, just leave it in place. Maybe you or a future owner will think of something to use it for later.

Retrofitting cable is something of an art form, but it can be learned. Things to consider as you plan a retrofit are which direction the floor joists go and where there are mechanical chases (ie for duct work) that you might be able to push wire through.