I liked this interview with Marcus Ranum titled Marcus Ranum on Network Security:
Q: In your opinion, what is the current weakest link in the network security chain that will need to be dealt with next year and beyond?
MJR: There are two huge problems: Software development and network awareness. The software development aspect is pretty straightforward. Very few people know how to write good code and even fewer know how to write secure code. Network awareness is more subtle. All through the 1990s until today, organizations were building massive networks and many of them have no idea whatsoever what's actually out there, which systems are crucial, which systems hold sensitive data, etc.
The 1990s were this period of irrational exuberance from a security standpoint - I think we are going to be paying the price for that, for a long time indeed. Not knowing what's on your network is going to continue to be the biggest problem for most security practitioners...
The real best practices have been the same since the 1970s: know where your data is, who has access to what, read your logs, guard your perimeter, minimize complexity, reduce access to "need only" and segment your networks. Those are the practices and techniques that result in real security. (emphasis added)
One way to begin this process is to hire an Enterprise Visibility Architect with the authority to figure out what is happening inside the organization.
Richard Bejtlich is teaching in DC and Europe in 2009. Register by 1 Jan and 1 Feb, respectively, for the best rates.