Guidelines for would-be corporate vigilantes

There are many ways to detect break-ins and a variety of options on how to proceed once you do. Here's a collection of insights from dozens of users, analysts and vendors on the techniques that work best.

n Use quality detection systems. You want to detect miscreant insider behavior as well as external hacking. Host-based auditing, network behavior statistics and traffic analysis are all good sources of security-related data that can alert you to abnormalities that may indicate a security incident. Keep in mind that intrusion detection systems (IDS) are all a little different. Some excel in NT, others in Unix or Novell, and some pick up anomalies and events that others don't. It's a good idea to use more than one IDS.

n Determine your first course of action once you detect an incident. Many people suggest isolating the source into a specific, noncritical part of your network. Others say cutting off the source of the attack is all they want to do. Your reaction should reflect your corporate security policy.

n Let your legal department know what's going on. If you ever have to get law enforcement authorities involved, you want to ensure you've taken the right steps. If your in-house counsel doesn't know how to proceed, strongly suggest he get advice from an experienced cyberattorney.

n Collect all systems logs from firewalls, routers and servers so you can identify what tools the attacker used and which of your vulnerabilities were exploited if you cut off the attack. Act upon this knowledge and reconfigure accordingly.

n Make sure all your auditing tools are active if you don't cut off the attack. You may want to increase the tools' sensitivity to capture more data points. Monitor the intruder's actions closely, so you can cut off the attack at any time you choose.

n Consider the use of forensic tools, especially if you have an insider hacking at your systems. Forensic tools will allow you to perform a sector backup of the suspect's hard disk with cryptographic seals to prevent tampering and assist in maintaining a quality chain of evidence. In addition, you may need to search the suspect's hard disk and floppies (including Zip drives and the like) for erased files and other hidden attributes. Don't forget to involve human resources personnel; they can keep you out of a heap of trouble.

n Attempt to trace the source of the attack. This is not easy, and often involves a lot of people with different organizations. Know whom to call at your ISP in the event of a breach. Be able to reach your contact 24-7 in case of an after-hours attack. ISPs coordinate with each other in many cases, and if you plan for the eventuality, you will be ahead of the game and able to react much faster.

n Have a game plan, especially if you call in law enforcement, which is more restricted in its ability and legal right to gather evidence than your company. Get legal advice regarding proper investigative techniques and evidence gathering so they will hold up in court. Recognize that investigative procedures and techniques can be disrupting, causing downtime and a drain in manpower.

n Strike back if you choose, but only with adequate legal counsel. There is a range of actions you can take - some more offensive than others.

n Prepare for the acts of man as much as for acts of God. Your disaster recovery people can handle floods, earthquakes and tornadoes. But can they handle a hacker?