How long is the warranty against rust on 2002 Chevrolet Malibu?

There is no factory warranty against rust on a 2002 Chevrolet Malibu. General Motors (GM) did not offer a nationwide, transferable rust warranty on its vehicles in that model year or for many years before. Any protection against rust would depend entirely on the terms of any specific, extended warranty purchased separately by the original owner. Even then, such warranties rarely covered all types of rust damage, and often had limitations on what constitutes "perforation".