"The existence of 'monoculture' on the Internet has both advantages and disadvantages. Its primary advantage is that increased standardization of systems generally allows for greater efficiencies (e.g., easier interoperability). On the other hand, monocultural environments are generally more vulnerable] to a single well-designed attack — a fact greatly exacerbated by the extensive interconnections that the Internet provides. * * *
A monoculture is highly vulnerable to attacks because once a successful attack on the underlying system is developed, it can be multiplied at extremely low cost. Thus, for all practical purposes, a successful attack on one system means that all similar (and similarly configured) systems connected to it can be attacked as well.
- "Overview" section: Information Technology for Counterterrorism: Immediate Actions and Future Possibilities, at 30.