The key thing to remember when dealing with insiders is they have access and, in most cases, will exploit the weakest link that gives them the greatest chance of access, while minimizing the chances that they get caught. Why try to break through a firewall and gain access to a system with a private address when you can find someone behind the firewall with full access to the system?Most people think of attackers as people with a huge amount of technical sophistication, who can walk through virtual cyber-walls and gain access to anything they want. But insiders take advantage of the fact they already have access, so many attack methods tend to be very low in technical sophistication. In some cases, if a pure insider or insider associate has partial access, then he will sometimes use additional techniques to increase his access. However, since he is typically not dealing with any security devices, most methods tend to be fairly straightforward.

It is also important to remember that to launch an effective attack, attackers need knowledge of the organization they are trying to attack. External attackers could spend weeks, if not longer, trying to acquire the information they need to launch a successful attack. In some cases, if they cannot gain enough knowledge, then they might decide to go against a different target. The insider has full knowledge of your operations. They know what is checked and what is not checked and can even test the system. For example, when they are trying to access their private shares, they could click on someone else's and see if anyone says anything. If they do this multiple times and nothing ever happens, they gain valuable knowledge that either access information is not being logged or not being watched. Because they have access to the operations, they either have detailed knowledge of how things operate, or they can gain it quickly by testing the system.

Everyone has heard the phrases "no pain, no gain" or "no risk, no reward." Every company in business has to take some level of risk; otherwise, the company will not be able to survive. If you say your company will have no risk of insider threat, then do not hire any employees. However, the second you hire one employee, your chances of having an insider attack increases. As you hire more employees, the risk keeps increasing. Obviously, most companies are willing to take that risk in order to grow their business.

This is also true of external attacks. As soon as you provide e-mail and Web services to the Internet, your chances of being attacked from the outside increase. However, your level of service and revenues also increase, so it is a risk worth taking.

The bottom line is you have to figure out what your acceptable level of loss is and then build in proper measures to protect against it. Many companies do not do this, throw caution to the wind, lose large amounts of money, and potentially go out of business due to insider attacks. It is much better to realize there will be some level of loss, but build in measures to minimize it to an acceptable level.

For example, hiring and giving everyone administrator access would be a huge potential for loss -- and not one I would be willing to accept. On the other hand, if you require that anyone needing administrator access has to justify why they need it, get sign-off by two executives, and go through a series of additional background checks before he or she is given the access, then this will help reduce the risk.

You might also put measures in place to rotate key positions so it would be harder for a person to cause damage over a long period of time. In addition, you might set up separation of duties in which two people are required to perform a certain function, which prevents a single person from causing damage.

None of these measures would stop a determined attacker, but they enable you to properly manage risk to an acceptable level. Insider attacks are likely to occur against your organization; the questions is whether you will be able to prevent most of them and, in cases where you cannot prevent them, whether you can detect them in a timely manner.

Dr. Eric Cole, Ph.D., is a security expert with more than 15 years of hands-on experience. Cole has experience in information technology with a focus on perimeter defense, secure network design, vulnerability discovery, penetration testing, and intrusion detection systems. He is the author of several books, including Hackers Beware, Hiding in Plain Site, Network Security Bible, and Insider Threat. He is the inventor of more than 20 patents, and is a researcher, writer, and speaker. Cole is a member of the Commission on Cyber Security for the 44th President and several executive advisory boards, and is CTO of the Americas for McAfee. Cole is involved with the SANS Technology Institute (STI) and SANS working with students, teaching, and maintaining and developing courseware. He is a SANS fellow, instructor, and course author.