This indicates an attack attempt to exploit possibly one or many vulnerabilities associated with Joomla! Googlemaps plugin.
The vulnerability is caused by a lack of sanitizing of the "url" parameter that is passed to "plugin_googlemap2_proxy.php". A remote attacker may be able exploit this to execute arbitrary script code within the context of the application or possibly cause a denial of service condition.
Joomla! any version containing Google Maps plugin
System Compromise: Remote attackers can execute arbitrary script code in the context of the affected site.
The vendor has removed the affect plugin from Joomla Base.
Upgrade to the latest version available.