  Advanced Persistent Threats or APTs are big challenges to the security of
government organizations or industry systems. These threats may result in
stealth attacks, but if the attack is confronted before the attacker end goal
has been achieved, the attackers could become aggressive by changing the mode
of attack or by resorting to some form of contingency plan, which might cause
unexpected damage. Therefore, the attack detection and the notification to the
system administrator should be done surreptitiously. This paper presents an
architecture, called Kidemonas, to silently detect the threat and secretly
report it to the user or the system administrator. This way the attacker is
deceived into carrying out the attack, without sending any clear signal so that
the defender can buy time to develop countermeasures to deal with the attack.
We consider several attack scenarios and perform a security analysis to
demonstrate the features of Kidemonas.
