In a constantly and intricately connected world that is going digital, cybersecurity is imperative to not just the success but also the survival of a business. The ubiquitous digital transformation is fueled by a convulsive growth of devices and data that are leading important innovations in the domain of cyber-physical systems. However, this growth has also enabled internal and external threats to skyrocket, depicting the inherent dichotomy. With an evolving threat landscape, a perpetrator has to be successful once, while the defenders have to continually succeed in fending-off attacks to protect critical infrastructure and digital assets. Businesses are facing a barrage of attacks, majority of which have a financial or an espionage motive. Against the hackers, businesses put forth an asymmetric and myopic struggle.Through this dissertation, I contribute to the modeling and analysis of security investments in cyber and supply chain networks considering network vulnerability also nonlinear budget constraints. The latter contributes significantly to the literature on variational inequality, game theory, and cybersecurity by being methodologically relevant to the application and solution of such problems. I also explore cooperation in terms of cybersecurity among firms in a network, providing a quantitative basis to information sharing to explore its financial and policy related benefits. This work extends the current literature in the cooperative game theory and cybersecurity domains.