This indicates an attack attempt to exploit a SQL Injection vulnerability in Joomla! Component Tumder.
The vulnerability is due to insufficient sanitizing of user supplied inputs in the application when handling a craft HTTP request. A remote attacker can exploit this to send a crafted query to execute SQL commands on a vulnerable server.
Joomla! Component Tumder version 2.1
System Compromise: Remote attackers can access or modify data in the database of the affected application
Currently we are unaware any vendor provided patch to address this issue.