Common Network Threats

Internal
• Insider users already have knowledge of the network and its available resources.
• Inside users typically have some level of access granted to them due to the nature of their job.
• Traditional network security mechanisms such as Intrusion Prevention Systems (IPS) and firewalls are ineffective against much of the network misuse originating internally.

External Threats
• It is most likely that external attackers do not have an intimate knowledge of a network, and because they do not already possess access credentials, their attacks tend to be more technical in nature.
• Before 2007, viruses were the leading contributor to financial losses for seven years in a row.

Network attacks are evolving in their sophistication and in their ability to evade detection.  Also, attacks are becoming more targeted and have greater financial consequences for their victims.