Data Siphoning in ICSs: Attack Tree and Role of Cryptoperiods

Siphoning of in-transit operational data is an especially concerning type of attack on modern-day industrial control systems (ICSs) - a type that can be conducted on its own or used as a reconnaissance stage for subsequent cyber-physical attacks. This is the first known research work to study the problem of operational data siphoning in ICSs from the perspective of threat modeling. The work introduces a comprehensive attack tree that outlines different options available to an adversary, as well as certain execution challenges, when conducting this type of attack. The attack tree is intended to serve as a roadmap for the development of more effective defences against data siphoning. The paper also discusses the important role of cryptoperiods as a critical defensive mechanism against data siphoning that is largely understudied in academic research and insufficiently elaborated on in industrial standards. Finally, the work points to the need for better coverage of data siphoning in MITRE ATT&CK framework, specifically its ICS matrix.