[Full-disclosure] Apache Illegal Request Handling Possible XSS Vulnerability

[Richard Moore]

Michal Majchrowicz wrote:
> Hi.
> I think now we can classify this as flaw in Apache. It accepts
> requests that simply make no sense. Take a look at this example:
> <script>alert(document.cookie);</script> /test.php
> <script>alert(document.cookie);</script>
> In some circumstances it may cause XSS vulnerability:
> <?php
>         echo $_SERVER['REQUEST_METHOD'];
>         echo $_SERVER['SERVER_PROTOCOL'];
> ?>

As Kradorex Xeron said, that's a flaw in the script. Apache needs
to let arbitrary verbs through to the PHP (or other server extension) 
otherwise tools like webdav that require additional verbs could not
be implemented. It is possibly arguable that it should restrict the
verbs to a single alphanumeric string, but it certainly can't be
counted on to be just GET/POST etc.

Cheers

Rich.

> I am now investigating other possible attacks.
> Regards Michal Majchrowicz.
> 
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Richard Moore, Principal Software Engineer,
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