Software products often need to vary in terms of functionality, but also in terms of quality attributes. We describe KumbangSec, which in an approach for modelling functional and security variability applying different architectural viewpoints. KumbangSec builds on an existing variability modelling method, Kumbang, by extending it with security engineering concepts. KumbangSec consists of a conceptualisation and a language implementing the conceptualisation. The semantics for the conceptualisation has been described using natural language; the syntax for the language has been defined in a grammar. KumbangSec can be supported with a configurator, which is an intelligent tool supporting derivation of products that each satisfy specific and different functional and security requirements. Such a tool, KumbangSec configurator, is currently being developed.