If you are using Nginx web server software and Magmi Data Import Tool, you should be aware of your Magento site security at risk. So, it is strongly recommend checking for this security concerns and get them fixed on your Magento site.
Nginx Web Server Misconfiguration
Byte.nl recently reported that some misconfigured Magento sites using Nginx web server software are vulnerable to attacks. Magento cache files have certain sensitive data information, which can be used to important information about the installation, database password, customer information, etc. Nginx Web Server Misconfiguration allows outside access to Magento cache files.