Intrusion Detection System (IDS) are a necessary part of any strategy for enterprise security. What are Intrusion Detection systems? CERIAS, The Center for Education and Research in Information Assurance and Security, defines it this way:

"The purpose of an intrusion detection system (or IDS) is to detect unauthorized access or misuse of a computer system. Intrusion detection systems are kind of like burglar alarms for computers. They sound alarms and sometimes even take corrective action when an intruder or abuser is detected. Many different intrusion detection systems have been developed but the detection schemes generally fall into one of two categories, anomaly detection or misuse detection. Anomaly detectors look for behavior that deviates from normal system use. Misuse detectors look for behavior that matches a known attack scenario. A great deal of time and effort has been invested in intrusion detection, and this list provides links to many sites that discuss some of these efforts"(http://www.cerias.purdue.edu/about/history/coast_resources/intrusion_detection/)

There is a sub-category of intrusion detection systems called network intrusion detection systems (NIDS). These systems monitors packets on the network wire and looks for suspicious activity. Network intrusion detection systems can monitor many computers at a time over a network, while other intrusion detection systems may monitor only one.

Who is breaking into your system?

One common misconception of software hackers is that it is usually people outside your network who break into your systems and cause mayhem. The reality, especially for corporate workers, is that insiders can and usually do cause the majority of security breaches. Insiders often impersonate people with more privileges then themselves to gain access to sensitive information.

How do intruders break into your system?

The simplest and easiest way to break in is to let someone have physical access to a system. Despite the best of efforts, it is often impossible to stop someone once they have physical access to a machine. Also, if someone has an account on a system already, at a low permission level, another way to break in is to use tricks of the trade to be granted higher-level privileges through holes in your system. Finally, there are many ways to gain access to systems even if one is working remotely. Remote intrusion techniques have become harder and more complex to fight.


How does one stop intrusions?


There are several Freeware/shareware Intrusion Detection Systems as well as commercial intrusion detection systems.

Open Source Intrusion Detection Systems

Below are a few of the open source intrusion detection systems:

AIDE (http://sourceforge.net/projects/aide) Self-described as "AIDE (Advanced Intrusion Detection Environment) is a free replacement for Tripwire. It does the same things as the semi-free Tripwire and more. There are other free replacements available so why build a new one? All the other replacements do not achieve the level of Tripwire. And I wanted a program that would exceed the limitations of Tripwire."

File System Saint (http://sourceforge.net/projects/fss) - Self-described as, "File System Saint is a lightweight host-based intrusion detection system with primary focus on speed and ease of use."


Snort (www.snort.org) Self-described as "Snort® is an open source network intrusion prevention and detection system utilizing a rule-driven language, which combines the benefits of signature, protocol and anomaly based inspection methods. With millions of downloads to date, Snort is the most widely deployed intrusion detection and prevention technology worldwide and has become the de facto standard for the industry."

Commercial Intrusion Detection Systems

If you are looking for Commercial Intrusion Detection Systems, here are a few of these as well:

Tripwire
http://www.tripwire.com

Touch Technology Inc (POLYCENTER Security Intrusion Detector)
Http://www.ttinet.com

Internet Security Systems (Real Secure Server Sensor)
http://www.iss.net


eEye Digital Security (SecureIIS Web Server Protection)
http://www.eeye.com

In 2004, online consumer spending was at a record $65.1 billion. More and more people are attracted to the ease of online shopping and are spending higher amounts. Unfortunately, the chances of becoming a victim of Internet fraud are also increasing. The Internet National Fraud Center Watch reported that the average loss to fraud victims for just the first six months of 2005 was $2,579. This is compared to the $895 average for all of 2004. Complaints relating to general merchandise purchases (goods never received or misrepresented) accounted for 30% of Internet fraud complaints, and auction purchases (goods never received or misrepresented) topped the list at 44%.

While many e-commerce Websites are reputable and have taken the necessary safety precautions to protect you, it never hurts to always proceed cautiously. If you are making an online purchase consider these easy steps:

1. Use only one credit card, preferably with a low credit limit, when making online purchases. Avoid using an ATM or debit card.
2. Be wary of unsolicited offers by sellers. The Internet National Fraud Information Center Watch reported that email, as a method of contact by Internet scammers was up 22% in 2004.While the offer may be legitimate, spammers like to use this tactic to side-step reputable sites that provide consumer protection for online purchases.
3. Use only reputable e-commerce websites that list a street address and telephone number in case you need to contact them directly.
4. Read the website’s privacy policy. Some websites may reserve the right to sell/give your information to a third party. Check the document to see if they allow an opportunity to “opt-out” of receiving special offers from third-party vendors or for permission to share your personal information.
5. Check for a lock symbol in the status bar at the bottom of your Web browser window. Also, do not provide your personal information if the website address doesn’t start with “https” (a sign that the site is using a secure server).
6. Choose only verified sellers. Check to see if the vendor is a verified member of a reputable third party such as the Better Business Bureau, VeriSign, or Guardian eCommerce. These third-party sites help to ensure online consumers will be protected when shopping or conducting e-commerce transactions.
7. Check that the delivery date posted is reasonable. If you have not dealt with the vendor on a regular basis, be wary of any Website that states the shipment will be delayed 20 or more days. Delivery dates of 7-10 days are more common.
8. Keep a paper trail of all online transactions. Print out a hard copy of the transaction and keep it in a file for future reference.
9. Be wary of website offers that just sound too good to be true. The Internet is littered with get rich quick scams and false advertising claims. Investigate all claims thoroughly before proceeding.
10. If you do not receive what you paid for, and the vendor will not return your emails or calls, contact your state’s Department of Consumer Affairs for further assistance.