I thought it might be helpful to post my understanding of these colors and to solicit feedback from anyone who could clarify these statements.
- Red Team: A Red Team is an adversary simulation team. The Red Team attacks the asset to meet an objective. This activity is called penetration testing in the commercial world.
- Blue Team: A Blue Team is a security posture assessment and evaluation team. The Blue Team determines the vulnerabilities and exposures of an enterprise. This activity is called vulnerability assessment in the commercial world.
- White Team: A White Team (or usually a "White Cell") controls the environment during an exercise. The White Cell provides the framework in which the Red Team attacks friendly forces. (Note that in some situations the friendly forces are called the "Blue Team." This is not the same Blue Team that conducts vulnerability assessments and evaluations. Blue in this case is simply used to differentiate from Red.)
- Green Team: The Green Team is usually a training group that helps the asset owners. Alternatively, the Green Team helps with long-term vulnerability and exposure remediation, as identified by the Blue Team. These descriptions are open for discussion because I haven't seen too many green team activities.
Did I miss any colors?