I want to know what type of server facebook uses ? If they use sql server , then is it vulnerable to sql injection ? Are all sql servers vulnerable to sql injection ? I just want to know this information and i have no intention of hacking as i have just started reading sql injection attacks and defense book
Facebook uses a custom version of MySQL. The site is almost certainly not vulnerable, since it's basically the biggest target on the web and people have been attacking it for years, mostly without success.
SQL injection vulnerability isn't a weakness in a database, it's a weakness in the application using the database. An SQL engine's job is to execute SQL statements, and injection works by tricking an application into sending statements that the developer didn't intend it to.