This paper presents an ontological
approach to perceive the current security status of the
network. Computer network is a dynamic entity whose
state changes with the introduction of new services,
installation of new network operating system, and
addition of new hardware components, creation of new
user roles and by attacks from various actors instigated
by aggressors. Various security mechanisms employed
in the network does not give the complete picture of
security of complete network. In this paper we have
proposed taxonomy and ontology which may be used to
infer impact of various events happening in the network
on security status of the network. Vulnerability,
Network and Attack are the main taxonomy classes in
the ontology. Vulnerability class describes various types
of vulnerabilities in the network which may in
hardware components like storage devices, computing
devices or networks devices. Attack class has many
subclasses like Actor class which is entity executing the
attack, Goal class describes goal of the attack, Attack
mechanism class defines attack methodology,