Hey folks! I've been diving into web and app security lately, and I've got some questions about the Same Origin Policy (SOP). From what I gather, SOP doesn't actually prevent requests from different origins; it just blocks the ability to read the response. So, if someone were to steal a user's session cookie, they could potentially use it in a cross-origin POST request (like making a bank transfer from a malicious site). This is, of course, assuming there are no CSRF tokens or other protections in place. I know CSRF attacks often exploit same-origin constraints, like through iframes or images if SameSite isn't set. Just to clarify for practical purposes, let's say the user has willingly shared their JSESSIONID. Am I understanding this correctly? Thanks in advance for your help with my possibly naive questions!
1 Answer
You're on the right track! If someone gets your session cookie, it can be a huge security risk unless there are additional protections in place. CSRF tokens are one of those extra layers to protect against this. And remember, browsers will usually perform a preflight check with an OPTIONS request before executing non-simple requests like POST. So they won't just blindly make the request! Check out the links for more info on preflight requests and the SameSite cookie attribute. It's important to have these defenses in place.
Thanks for clarifying! I get the preflight checks now, but that only applies to CORS, right? If there's no CORS setup and the attacker has the user's session, does that mean it's essentially game over without other security measures like CSRF or SameSite?