How to raise students' security awareness in programming?
Make it into an assignment/game. Each student creates a project that is passed to another, randomly chosen student, to hack. Give points for both the project and the "hacking" results. The hacking assignment should also be graded.

Security has to be taught and the value learned, usually painfully. I have lived through many "no one will do that!" only to have a product, or network, broken because someone did.