What security issues should I look out for in PHP

Question

I just starting out learning PHP, I\'ve been developing web apps in ASP.Net for a long time. I was wondering if there are any PHP specific security mistakes that I should be

Answer 1

Often introductory tutorials don't talk at all about checking data from users. Like all programming environments, never trust the data you get from users. Learn to use functions like is_numeric(), isset(), and mysql_real_escape_string() to protect your system.

There are also features that allow you to access remote files, and other creative things. I'd avoid those until you have a good understand of how and when they work (often they are disabled for security reasons).