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[whatwg] element "img" with HTTP POST method

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Thu, 9 Dec 2010 16:46:47 -0800
Message-ID: <AANLkTimv-VFZZcYbqb5kn_AZ5g0d_YJ=CYXO2WbsZsom@mail.gmail.com>
On Thu, Dec 9, 2010 at 11:01 AM, Adam Barth <w3c at adambarth.com> wrote:
> We've seen use cases for a similar feature for iframes and hyperlinks.
> ?For example:
>
> <a href="/logout" post-data>Logout</a>
>
> would be more semantically correct that just <a
> href="/logout">Logout</a> because it would generate a POST instead of
> a GET.

Why wouldn't <form method=post
action=/logout><button>Logout</button></form> work, with some CSS to
make it look like a link if you wanted that?


On Thu, Dec 9, 2010 at 11:41 AM, Philipp Serafin <phil127 at gmail.com> wrote:
> There are quite a number of older web forums that sanitize their HTML using black lists and would not strip new attributes like "post-data". For malicious users, it would be very easy to include e.g. <img src="./do_post.php" post-data="thread_id=42&post_content=Go visit (some spam URL)"> in their signature and have users doing involuntary posts by simply viewing a thread.

Indeed.  You shouldn't be able to trigger POSTs from involuntary
actions.  They should always require some sort of user input, because
there is simply *far* too much naive code out there that is vulnerable
to CSRF.

~TJ
Received on Thursday, 9 December 2010 16:46:47 UTC

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