Updated post at https://ishaqmohammed.me/posts/resources-for-application-security/
Some good resources for getting started with application security
Note: The resources which i have put are those which i will be using in my application security learnings, feel free to use it for your learning purpose only and if you have any suggestions dm me on Twitter
- Development
 - Application Security Books and online resources
 - Hands on CTF
 - SAST and DAST
 - Securing Applications
 - Further reading
 
- PHP with MySQL Essential Training by lynda
 - PHP: Object-Oriented Programming
 - Learning PHP, MySQL & JavaScript, 4th Edition With jQuery, CSS & HTML5
 - Web technology for developers by Mozilla
 
- Web Application Hacker handbook
 - Mastering Modern Web Penetration Testing
 - Hacker101
 - Application Security Wiki
 - CodePath Web Security Guides
 
- A good collection of CTFs for learning SAST and DAST
 - A completely open code audit challenge!
 - Securify BV spot the bug challenges
 - Web Security Academy
 - Hacker101 CTF
 
Once done reading these 2 books above, try implementing the techniques you learnt from them on this CTF challenges and the application you developed in task 1
Once we learn how to perform SAST and DAST for the application, we also need to know how to secure it, for which the below books and resource are great
- The Tangled Web – A Guide to Securing Modern Web Applications
 - Essential PHP Security
 - SQL Injection Attacks and Defense
 - PHP Security
 - Survive The Deep End: PHP Security
 
- The Browser Hacker's Handbook
 - OWASP Testing Guide v4
 - Web Hacking 101
 - Writing Secure Code, 2nd Edition
 - awesome-web-hacking
 - awesome-web-security
 
Application-Security-Engineer-Interview-Questions