We can compare the URL to the referrer header
which makes life easy (we would need access to the request but I
think this is coming soon.)
True, once we have access to the request we could easily add referrer
header checking.
or (user
+
reason) -> token, where "reason" would be some description of the
intended change like "edit:Main.Test" or
"rights:SomeUser+comment-edit"?
This idea sounds like it would require a
lot of extra infrastructure, maybe I am not seeing it right.
No, the "reason" would contain only the important part of the things
that are currently usually in the URL, like document name and action.
From the viewpoint of token component the exact content doesn't matter,
it should just contain enough information to differentiate editing of
different things.
The reason for this idea is that we would need to give the same URL to
both getToken and isTokenValid as an argument, but those methods are
usually called from totally different places. So I think it is easier to
give the (somewhat simplified) reason instead of trying to come up with
the same URL after several redirects.
For example, URLS for editing and deleting a page clearly differ in the
action part (/delete/Main/WebHome vs. /save/Main/Webhome), but most
administrative tasks go to /admin/XWiki/XWikiPreferences, are redirected
to saverights.vm and only differ in the query part of the URL. Pages can
also be edited over /preview/... with correct parameters. Changing
access rights sometimes use /save/... as URL, etc.
WDYT?
Alex
> getToken would return different tokens for
different pages/"reasons" and
> isTokenValid would need to provide the same url/"reason" for check to
> succeed.
>
>
>> Caleb
>>
>>> Thanks,
>>> Marius
>>>
>>>> If a configuration parameter is specified to disable the component,
getToken returns "" and isTokenValid
>>>> returns true.
>>>>
>>>> WDYT?
>>>>
>>>> Caleb
>>>>
>>>>
>>>> Caleb James DeLisle wrote:
>>>>> Sergiu Dumitriu wrote:
>>>>>> On 03/10/2010 07:44 PM, Caleb James DeLisle wrote:
>>>>>>> Take a look at the "sammy is my hero" worm, myspace
sent a hash to the user like the one you propose,
>>>>>>> the worm made the required get request to get the hash, then
made the post along with the hash.
>>>>>>> What prevents javascript from opening the page with the hash
in an iframe and then reading in the iframe
>>>>>>> to get the hash, then creating a form with the required data
and posting it to the save action?
>>>>>>>
>>>>>>> If we were to combine a requirement for post requests with
checking of the referrer header, then we
>>>>>>> would block links, forms and javascript based attacks leaving
only an attack through older versions
>>>>>>> of flash which support referrer forgery and at this point the
difficulty of the attack becomes such that
>>>>>>> we need to consider a wider array of attack vectors.
>>>>>> Sammy also required that XSS is enabled.
>>>>>>
>>>>>> Protecting from attacks originating in the wiki is kind of
impossible at
>>>>>> the moment, since JS can be inserted anywhere, and there's no
(nice) way
>>>>>> to prevent attacks from JS inside the application. As long as JS
can be
>>>>>> inserted, an attacker can do all the steps that the client would
do to
>>>>>> perform an action.
>>>>>>
>>>>>> The secret token works as a prevention mechanism when the attack
comes
>>>>>> from another site because the browser security model prevents the
attack
>>>>>> code to read the form.
>>>>> I just did a few tests on iframes and I was wrong, they do have good
same origin policy.
>>>>>
>>>>> Caleb
>>>>>
>>>>>>> Caleb
>>>>>>>
>>>>>>>
>>>>>>> Alex Busenius wrote:
>>>>>>>> Unfortunately, using POST requests instead of GET
requests is not
>>>>>>>> enough. It will not prevent attacks that use forms and/or
JavaScript to
>>>>>>>> generate POST requests.
>>>>>>>>
>>>>>>>> Alex
>>>>>>>>
>>>>>>>>
>>>>>>>> On 03/09/2010 02:48 PM, Caleb James DeLisle wrote:
>>>>>>>>> I had thought about proposing this myself but decided
against it because it seems
>>>>>>>>> to me like a workaround for problems which can be
solved in other ways.
>>>>>>>>>
>>>>>>>>> Suppose we were to add a check to the actions which
alter data which made sure the request method
>>>>>>>>> was 'post' and made it configurable in one of
the configuration files? We would have
>>>>>>>>> to look over the default skins for incorrect links
and leave the configuration
>>>>>>>>> option off by default for backward compatibility at
least until the next major version
>>>>>>>>> but we could provide wiki operators the ability to
prevent CSRF.
>>>>>>>>>
>>>>>>>>> Caleb
>>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> devs mailing list
>>>>>>>> devs(a)xwiki.org
>>>>>>>>
http://lists.xwiki.org/mailman/listinfo/devs
>>>>>>>>
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