Release It!, 2nd Edition

The Principle of Least Privilege

The principle of “least privilege” mandates that a process should have the lowest level of privilege needed to accomplish its task. This never includes running as root (UNIX/Linux) or administrator (Windows). Anything application services need to do, they should do as nonadministrative users.

I’ve seen Windows servers left logged in as administrator for weeks at a time—with remote desktop access—because some ancient piece of vendor software required it. (This particular package also was not able to run as a Windows service, so it was essentially just a Windows desktop application left running for a long time. That is not production ready!)

Software that runs as root is automatically a target. Any vulnerability ...