To plan and implement a good security strategy, first be aware of some of the issues which determined, motivated attackers exploit to compromise systems.
1.3.1. Threats to Network Security
Bad practices when configuring the following aspects of a network can increase the risk of attack.
188.8.131.52. Insecure Architectures
A misconfigured network is a primary entry point for unauthorized users. Leaving a trust-based, open local network vulnerable to the highly-insecure Internet is much like leaving a door ajar in a crime-ridden neighborhood — nothing may happen for an arbitrary amount of time, but eventually someone exploits the opportunity.
184.108.40.206.1. Broadcast Networks
System administrators often fail to realize the importance of networking hardware in their security schemes. Simple hardware such as hubs and routers rely on the broadcast or non-switched principle; that is, whenever a node transmits data across the network to a recipient node, the hub or router sends a broadcast of the data packets until the recipient node receives and processes the data. This method is the most vulnerable to address resolution protocol (ARP) or media access control (MAC) address spoofing by both outside intruders and unauthorized users on local hosts.
220.127.116.11.2. Centralized Servers
Another potential networking pitfall is the use of centralized computing. A common cost-cutting measure for many businesses is to consolidate all services to a single powerful machine. This can be convenient as it is easier to manage and costs considerably less than multiple-server configurations. However, a centralized server introduces a single point of failure on the network. If the central server is compromised, it may render the network completely useless or worse, prone to data manipulation or theft. In these situations, a central server becomes an open door which allows access to the entire network.