ABSTRACT
Intrusion in information system security simply means the attempts or actions of unauthorized entry
into an IT system. This action ranges from a reconnaissance attempt to map any existence of vulnerable
services, exploitation/real attack, and finally the embedding of backdoors. Such a malicious process can
result in the creation of an illegal account with administrator privilege upon the victim machine.
Actually, there have been several approaches or technologies designed to prevent such unwanted actions.
Hence, the intrusion prevention system (IPS) is really not something new in the world of information
system security. Some examples of prevention approaches or systems in existence today include anti-
virus, strong authentication, cryptography, patch management, and firewalls. Anti-virus systems exist to
prevent malicious programs such as viruses, worms, backdoor programs, etc. from successfully being
embedded or executed within a particular system. Patch management ensures effective deployment of the
latest security fixes/patches so as to prevent system vulnerabilities from successfully being exploited.
Firewalls exist to prevent unwanted access to some particular systems. Cryptography exists to prevent any
attempts to disclose or compromise sensitive information. Strong authentication exists to prevent any
attempts to fake an identity in an effort to enter a particular system.
