I am going to host a web site in Amazon EC2 instance which would be a Linux instance. My web application will be developed using PHP, Apache and MySql. As I am new to Linux and Amazon EC2 environment, what are key areas in security should I consider to protect my server? This may be very very generic question as the security itself a vast area. But I need to kick start with most imporant points. That way I would be able to track down all those areas one by one.
It should be no different with a normal server connected to Internet. A good method is to set up firewall using like iptables. And EC2 only open several ports by default actually.
The different is that it is managed by Amazon EC2. You can not totally avoid EC2 to read/write your files in EC2 since they control the hypervisor and they can do everything. But I do think they will do this. If your data should be really really secure, EC2 (and other cloud platform) is not a good choice.