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.
This archive was generated by hypermail 2.1.3 : Mon Apr 23 2007 - 16:55:11 PDT