Validating and Sanitizing User Input

Abstract

Your users’ data is useless if it isn’t used. And yet, paradoxically, that data is endangered by the very act of accessing it. Particularly dangerous are the accesses occasioned by users’ queries, submitted typically via form input. Legitimate users may accidentally make requests that turn out to be dangerous; illegitimate users will carefully craft requests that they know are dangerous, hoping that they can slip them past you.