Apache/PHP REQUEST_METHOD XSS Vulnerability

["Michal Majchrowicz" <m.majchrowicz () gmail com>]

There exist a flaw in a way how Apache and php combination handle the
$_SERVER array.
If the programmer writes scrip like this:
<?php
              echo $_SERVER['REQUEST_METHOD'];
?>
He will assume that REQUEST_METHOD can only by: GET,POST,OPTIONS,TRACE
and all that stuff. However this is not true, since Apache accepts
requests that look like this:
GET<script>alert(document.coookie);</script> /test.php HTTP/1.0
And the output for this would be:
GET<script>alert(document.coookie);</script>
Of course it is hard to exploit (I think some Flash might help ;)) and
I don't know if it is exploitable at all. But programmers should be
warned about this behaviour. You can't trust any  variable in the
$_SERVER table!
Regards Michal Majchrowicz.

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