Re: extract($_POST)
| From: | ed at home dot homes2see dot com | Date: | Fri, 25 Oct 2002 14:34:06 +0000 |
| Subject: | Re: extract($_POST) | ||
| References: | 1 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-121459@lists.php.net to get a copy of this message | ||
I thought of this was well and into the PHP documentation about this
option. Here's a side note that the documentation includes:
Not all user agents will set this, and some provide the ability to modify
HTTP_REFERER as a feature. In short, it cannot really be trusted.
Even thought it's not a sure-fire method, it can be included along with
other security methods to increase the amount of security on a script.
Ed Curtis
On Fri, 25 Oct 2002, John Nichel wrote:
> And if you want to take it a step further, to ensure that the values are
> submitted from YOUR form, check the $_SERVER['HTTP_REFERER'] to see if
> it's coming from your domain | page.
>
> Paul Nicholson wrote:
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> > On Friday 25 October 2002 11:23 am, Johnson, Kirk wrote:
> >
> >>>And what should these precautions be? If a malicious user can submit
> >>>his own form and you are looking for a POST variable, how can you
> >>>ensure that $admin came from your form and not that user's?
> >>
> >>The problem is when a cracker uses form variables in an attempt to set the
> >>values of "flag" variables kept only in the session, for example, $isAdmin.
> >>As far as the form variables *you* put in your form, it doesn't matter
> >>whether the user submits your form or a form they made themselves. Those
> >>form variables are just data you are trying to collect.
> >>
> >>With register_globals on, PHP takes *all* variables (GET, POST, COOKIE)
> >>received from the client and assigns them to global variables. So if the
> >>user posts a value for $isAdmin, she can give herself admin privileges.
> >>
> >>The key is to retrieve *only* the form variables *you* put in the form from
> >>the the $_POST array. So don't write a loop and grab *everything* from that
> >>array.
> >>
> >>Kirk
> >
> >
> > Exactly! Not only should you retrieve *only* the vars you need from POST,
> > you should also filter them to make sure they contain what you're looking
> > for.....is_alpha($_POST['name']). And no, php doesn't have an
> > 'is_alpha'
> > function....I created that as part of a filtering class.
> >
> > ~Paul
> >
> >
> > - --
> > ~Paul Nicholson
> > Design Specialist @ WebPower Design
> > "The web....the way you want it!"
> > paul@webpowerdesign.net
> >
> > "It said uses Windows 98 or better, so I loaded Linux!"
> > Registered Linux User #183202 using Register Linux System # 81891
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>
>
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