What Are Security Best Practices for WordPress Plugins and Themes? [closed]
Use Nonces (when not using Settings API) Plugins and Themes should explicitly provide Settings-page nonce checking, if not using the Settings API: WordPress Nonces (Codex) WordPress Nonces (Mark Jaquith) Improving security in WordPress plugins using Nonces (Vladimir Prelovac) 5 tips for using AJAX in WordPress > 3. Use nonces and check for permission (Gary Cao)