Minimum Software

From Sysadmin

Software should only be installed on a system if it is necessary for the proper functioning of the system. Any software running on a system is a potential vector to break into the system. This is particularly true for software that listens on the network, such as most daemons.

Starting a deamon and and unintentionally leaving it running is a common occurrence in real-world system administration. Similarly the sysadmin might shutdown an unneeded daemon only to have it start again on the next reboot because it was not disabled on boot. If the software is not there it cannot start and cannot be a vector to attack the system.

Any software running on the system must be subject to security updates. Any updates add potential instability as software packages, particular in the open source world, are often a mesh of dependencies. If the software is not present it doesn't need updates and can't cause or add to any instabilities.