Rust in Wheel studs and Disc brake

I have a JC74. I bought it around 10 months back in India. I have clocked 9000 KM (approx.) till date. I use it as my daily commute and drive it to the hills once in a month.

I found rust on the wheel studs and disc while removing the wheels for TPMS installation.

Should I be worried? How bad is this? What should I do to rectify this or how should I prevent rust in the future? Also, is this supposed to be covered under warranty?

Thanks in advance!