documents, based mainly on -
published papers where a consistent mathematical description of cyberspace and
various types of Cyber-Attacks and protection measures are presented, a holistic
mathematical approach to a rigorous description of Advanced Persistent Threat
(APT) actorsí modus operandi through various scenarios and Cyber Kill Chain
stages . After referring  to the various elements of
Cyber-Attacks we propose some techniques (via 5 scenarios) of tracking the
modus operandi of the most sophisticated and non-linear cyber actors, the
Advanced Persistent Threat actors that are usually nation-state or nation-state
backed and usually stay undetected for an extended time in later stages of
Cyber Kill Chain in defendersí networks.
of cyber assets, vulnerability of cyber assets, node supervision,
sophistication of an attack germ of cyber-attack, cyber defense, proactive
cyber protection, Advanced Persistent Threat (APT) actors, Indication of
Compromise (IOC), Tactics, Techniques and Procedures (TTPs).