Got rust on chain and cassette I have a pretty new bike (5 years) and just recently got all the transmission very rusty (https://imgur.com/a/AlCts9b). Several things happened:

· Degreased it thoroughly (probably too much)

· Lubricated the chain and cassette with wax lube (brand: squirt). I've read that regular lube protects the chain from rust but I don't know about this one, couldn't find a thing.

· Did a 7-day trip with the bike leaving it most days outside, so it got exposed to some humidity but I had no option of leaving it inside.

if someone knows which one is the most probable culprit it would be helpful so I don't make the same mistake twice.

Now that it's rusty though I'm unsure about what to do. I tried to clean the rust without dissassembling the whole drivetrain but it wasn't very effective. Should I dissassemble everything and try to get the rust out or just lube it instead of using wax and use it regularly?
Note to readers -  Squirt is a wax based dry lube, the chain was not hot waxed.

The rust is cosmetic. Its been caused because you stripped the protective coatings with the degreaser and did not cover the chain and cassette completely in a protective layer.  Did you dry the chain before applying the lube and did you drown the chain then wipe off excess? 

Did you reapply lube over the 7 days? A dry lube won't last that long. 

For De greasers I use a citrus based cleaner or specific bike 'chain cleaner as these are not as harsh as many of the automotive ones. They clean the chain without stripping it bare of protection.

Dry lube is great, in dry conditions and OK in damp conditions but you need to reapply it regularly and use the right amount (which is heaps, drown the chain then wipe dry).  Wet lube offers better protection in wet conditions. 

You can get plated chains if the rust bothers you.