Internal network security is, more often than not, underestimated by administrators. Very often, such security does not even exist, allowing one user to easily access another user’s machine using well-known exploits, trust relationships and default settings. Most of these attacks require little or no skill, putting the integrity of a network at stake.
Most employees do not need and should not have access to each other’s machines, administrative functions, network devices and so on. However, because of the amount of flexibility needed for normal operation, internal networks cannot afford maximum security. On the other hand, with no security at all, internal users can be a major threat to many corporate internal networks.
A user within the company already has access to many internal resources and does not need to bypass firewalls or other security mechanisms which prevent non-trusted sources, such as Internet users, to access the internal network. In fact, 80% of network attacks originate from inside the firewall (ComputerWorld, January 2010)
Top 7 Internal Threats: