The same-origin-policy is one of several models that web browsers use to determine which JavaScript files in a webpage should be executed. This is determined by the domain (the origin).

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14
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2answers
34k views

Why is the Access-Control-Allow-Origin header necessary?

I understand the purpose of the Access-Control-Allow-Credentials header, but can't see what problem the Access-Control-Allow-Origin header solves. More precisely, it's easy to see how, if ...
10
votes
2answers
3k views

Using iframes to sandbox untrusted code

I'm trying to create an extensible platform, where my site will provide a model and some views (both client-side, in the browser) and third party sites may add their own views as well. The goal here ...
5
votes
1answer
558 views

Child iFrame hash verification of parent iFrame content

Consider the following scenario: Alice wishes to browse Victor's website while on the job at Initech. Victor's website is hosted on an alternative domain name system to which Initech's DNS does not ...
2
votes
3answers
482 views

Flash ignores Content-Type header, allowing XSS?

I recently read that the Flash plugin ignores the Content-Type header in certain circumstances. In particular, you can give Flash a URL, and the Flash plugin will happily fetch the content at that ...
36
votes
4answers
10k views

Why is the same origin policy so important?

I can't really fully understand what same origin domain means. I know it means that when getting a resource from another domain (say a JS file) it will run from the context of the domain that serves ...
17
votes
4answers
2k views

What is the point of the same-domain rule for xmlhttprequest when script tags/JSONP can cross domains?

I get that I don't want a page loaded from stackoverflow.com to be able to request gmail.com on my behalf and read my email--but this seems to be simply a cookie issue. Since JSONP bypasses ...
9
votes
2answers
525 views

User-specific Subdomains : JavaScript security

If I provide a public-facing website for users on my website at their own subdomain (e.g. bob.myapp.com) under their own control, can I allow them to execute arbitrary JavaScript without putting my ...
4
votes
1answer
627 views

Does returning `Access-Control-Allow-Origin: *` weaken the security of JSON GET responses?

The W3C CORS recommendation states: Certain types of resources should not attempt to specify particular authorized origins, but instead either deny or allow all origins. ... 3. A GET ...
3
votes
1answer
649 views

Access-Control-Allow-Origin wihout AJAX

The post at http://security.stackexchange.com/a/43456/8340 (incorrectly?) states No, as long as the CORS Access-Control-Allow-Origin is at its default restrictive value. This prevents the outer ...
3
votes
1answer
230 views

What servers or clients are immune to related-domain cookie attacks? (*.example.com)

In this question, I want to identify browsers, servers, or implementations that are immune from related domain cookie attacks (e.g. a.example.com vs b.example.com). Lacking any tangible solution, ...