On the Insane Security blog there's a new post recommending (despite the title of the post) the use of something that comes standard to every PHP5 release - the filter extension - and how it can help you protect your application and its data.

Yesterday while browsing some security tagged discussions on stackoverflow.com I've noticed someone mentioned some filter_ prefixed PHP functions. At first I thought they were some custom written ones, but on a quick check it turned out that there really where this functions. I was shocked. Anyway, let's digg into it...

The post covers all of the filters (validate, sanitize and "other") as well as the functions the extension includes like filter_has_var, filter_input and filter_var.