It might be an idea to post this on Mammalwatching.
The bicoloured tail suggests it "should" be the Red Rajah Rat Maxomys surifer but the colouration is weird, and also it looks less like a Maxomys and more like a Niviventer to me. The closest Niviventer in appearance is N. fulvescens but I don't know if that is found as far south as Taman Negara (and, again, that colour combination looks weird unless there is some artifact of the lighting).
