In our apache error log (/usr/local/apache/logs/error_log) for one of our servers we are seeing a shell command running quite often which is throwing an error, it looks like this:
sh: list_price: command not found
list_price is a field we use in an ecommerce system on over 50 sites and certainly nothing suspicious. The issue is that we have no idea how this is being passed to the shell - we have checked all occurrences of exec() and system() and we just cannot see how this would be getting passed through. Is there any way we can detect more easily what the source of this could be as there is nothing more meaningful being output that what i put above. FYI this is on a server running CentOS 5 and the sites in question are all PHP.