what is an insider attack computer

insider attack -
  An attack to the network or the computer system by some person with authorize system access is known as insider attack .It is generally performed by dissatisfaction or unhappy inside employed or contractor.The motion of the insider attack could be revenge or greed . It is comparatively easy for an insider to perform a cyber attack as he is well aware of the policies , process ,IT architecture,
and weekends of the security system. More ever the attacker have an access to the network. Therefore it is comparatively easy
for a insider attackers to steel sensitive information , crash the network etc.in the most of cases the reason for insider attack is when a employee is fried or assigned new roles in an 
organisation, and the role is not reflect in the IT policies .This open a venerability window for the Attacker .The insider attack could be prevented by planning and installing an internal 
detection system (IDS) in the system.