  Industry 4.0 envisions a fully automated manufacturing environment, in which
computerized manufacturing equipment--Cyber-Physical Systems (CPS)--performs
all tasks. These machines are open to a variety of cyber and cyber-physical
attacks, including sabotage. In the manufacturing context, sabotage attacks aim
to damage equipment or degrade a manufactured part's mechanical properties. In
this paper, we focus on the latter, specifically for composite materials.
Composite material parts are predominantly used in safety-critical systems,
e.g., as load-bearing parts of aircraft. Further, we distinguish between the
methods to compromise various manufacturing equipment, and the malicious
manipulations that will sabotage a part. As the research literature has
numerous examples of the former, in this paper we assume that the equipment is
already compromised, our discussion is solely on manipulations.
  We develop a simulation approach to designing sabotage attacks against
composite material parts. The attack can be optimized by two criteria,
minimizing the "footprint" of manipulations. We simulate two optimal attacks
against the design of a spar, a load bearing component of an airplane wing. Our
simulation identifies the minimal manipulations needed to degrade its strength
to three desired levels, as well as the resulting failure characteristics. Last
but not least, we outline an approach to identifying sabotaged parts.
