According to cvedetails.com, more than 1,305 vulnerabilities have been found in the Linux core since 1999. Sixty-eight of these were in 2015. Most of them don't cause many problems (they are marked as Local and Low), and some may cause problems only if they are attached to certain applications or OS settings. In reality these numbers are not that big, but the core is not the entire OS. There are also vulnerabilities found in GNU Coreutils, Binutils, glibs and, of course, user applications. Let's take a look at the most interesting of the bunch.
*nix systems are by default provided with remote management tools, while the method of storing and format of configuration files allows you to rapidly distribute the updated version of settings by simply copying them to the node. This scheme will be good enough for up to a certain number of systems. However, when there are several dozens of servers, they cannot be handled without a special tool. This is when it becomes interesting to have a look at configuration management systems that allow a programmable rather than manual configuration of servers. As a result, the systems can be configured quickly and with fewer errors while the administrator will get the comprehensive report. Also, a CM system knows how to keep track of all changes in the server while supporting the desired configuration.