I know about following security attacks on php applications (html,php,js).
- SQL Injection
- Session Hijacking /Fixation
- Code Injection
Remote file injection
Should i know about any other or have i missed any?
Yes, there's definitely a lot more. I suggest that you start by reading about the OWASP Top 10. Every web developer needs to be familiar with each of those categories of threats.
In addition, here are some good introductions to web security:
P.S. Some other categories to make sure you know about: path traversal, session management, secure password storage, clickjacking, phishing, site-wide SSL.
SANS publish a list of Top 25 Dangerous Software Errors every year. Some (or more) of these will be relevant to your application.
There may be other vulnerabilities in your product that are not covered in the SANS or OWASP lists, but these are a great place to start. Because they're so common, attackers (including script kiddies) and researchers will be able to find and exploit any vulnerabilities found here very quickly. It's also a great exercise to try and identify these vulns in your code, work out how you will solve them, whether you've got (or need) any tools to help and how you'll fit such work into your development cycle to ensure the vulns don't get reintroduced.
At some point you'll need to strike out on your own, and examine your application specifically. That's the only way you'll find issues specific to your domain, by looking at how your users use your app and how "your" attackers abuse it.
Maybe you might want to have a look at this post.