Server security is as important as network security because servers often hold a great deal of an organization's vital information. If a server is compromised, all of its contents may become available for the attacker to steal or manipulate at will. The following sections detail some of the main issues.
18.104.22.168. Unused Services and Open Ports
A full installation of Red Hat Enterprise Linux 7 contains 1000+ application and library packages. However, most server administrators do not opt to install every single package in the distribution, preferring instead to install a base installation of packages, including several server applications.
A common occurrence among system administrators is to install the operating system without paying attention to what programs are actually being installed. This can be problematic because unneeded services may be installed, configured with the default settings, and possibly turned on. This can cause unwanted services, such as Telnet, DHCP, or DNS, to run on a server or workstation without the administrator realizing it, which in turn can cause unwanted traffic to the server, or even, a potential pathway into the system for attackers. Refer To Section 2.2, “Server Security”
for information on closing ports and disabling unused services.