> Cross-Site Request Forgery (CSRF/XSRF) is an attack that forces an end user to execute unwanted actions on a web application in which they're currently authenticated. CSRF attacks specifically target state-changing requests, not theft of data, since the attacker has no way to see the response to the forged request. - OWASP
When you are logged in to a certain site, you typically have a session. The identifier of that session is stored in a cookie in your browser, and is sent with every request to that site. Even if some other site triggers a request, the cookie is sent along with the request and the request is handled as if the logged in user performed it.
- [Messenger.com CSRF that show you the steps when you check for CSRF - Jack Whitton](https://whitton.io/articles/messenger-site-wide-csrf/)
- [Paypal bug bounty: Updating the Paypal.me profile picture without consent (CSRF attack) - Florian Courtial](https://hethical.io/paypal-bug-bounty-updating-the-paypal-me-profile-picture-without-consent-csrf-attack/)
- [Hacking PayPal Accounts with one click (Patched) - Yasser Ali](http://yasserali.com/hacking-paypal-accounts-with-one-click/)
- [Add tweet to collection CSRF - vijay kumar](https://hackerone.com/reports/100820)
- [Facebookmarketingdevelopers.com: Proxies, CSRF Quandry and API Fun - phwd](http://philippeharewood.com/facebookmarketingdevelopers-com-proxies-csrf-quandry-and-api-fun/)
- [How i Hacked your Beats account ? Apple Bug Bounty - @aaditya_purani](https://aadityapurani.com/2016/07/20/how-i-hacked-your-beats-account-apple-bug-bounty/)
- [FORM POST JSON: JSON CSRF on POST Heartbeats API - Dr.Jones](https://hackerone.com/reports/245346)