I do agree that SNORT is one of the most popular when you are learning about IDS, but it is possible to attack the IDS engine in a very easy way: 1) evasion; 2) DoS; 3) Flse Positive; 4) you name it...
That isn't a SNORT's weakness, it is a technology limitation: pattern matching. This is very easy to take advantage of the pattern itself - in bad sense... I think the best approach is when vendors get the knowledge of how the vulnerabilties work, istead of how the exploits exploit the vulnerability. This is so reactive that any new exploit / worm variant will require a new signature. Keep in mind that when you know how the vulnerability can be exploited is better than know how so many exploits works, but it is not that easy! A signature database based on pattern is easier but gives you worng sense of protection, and this worse than no protection. That said, IMHO, anomaly detection + signature database based on vulnerabilties + behavior detection + any other approach other than pattern means BETTER SECURITY / PROTECTION. My 2 cents. Nelson Brito ([EMAIL PROTECTED]) Senior IPS Engineer & Pen-tester -----Original Message----- From: [EMAIL PROTECTED] Sent: Thursday, October 04, 2007 11:29 PM To: [email protected] Subject: Re: IDS detection approaches Hola, I would completely go with a signature based IDS. Anomaly based IDS will not give you the greatest results. For signature base I highly recommend SNORT. It is probably one of the best IDS out there. Now I'm not just saying this as a "ooh open source is the best". I truely believe this. I actually use to be a huge Cisco buff and just dealt with Cisco IDS. However, at my current job I am a security analyst and have to analyze events from Cisco, IIS, Juniper, etc, and SNORT beats them all. Mainly for the fact that you are able to see the packet payload and are able to make the decision if something is malicious based on the actual payload and not just the signature that is triggered (like some IDS). Also, when a new threat emerges usually SNORT users will create a signature to combat the threat. The other vendors create the signatures for you and it usually ends up to be like 3 months after the threat was actually a realistic threat. And on top of it the vendor signatures usually give out huge amount of false positves. Then again, an IDS is only as good as who tunes it. If you take A NY IDS and turn it on in a production network you will have so many false positives I garuntee you will miss actual threats. Every IDS (including SNORT) has to be tuned for the production network it is on. Finally, make sure to place the IDS behind the firewall. If you place it in front of the firewall you will receive so much traffic that it is just not valuable data. You have a firewall, so let the firewall do its job and block the already known bad activity, and catch what gets through the firewall with a IDS. -FF ------------------------------------------------------------------------ Test Your IDS Is your IDS deployed correctly? Find out quickly and easily by testing it with real-world attacks from CORE IMPACT. Go to http://www.coresecurity.com/index.php5?module=Form&action=impact&campaign=intro_sfw to learn more. ------------------------------------------------------------------------ ------------------------------------------------------------------------ Test Your IDS Is your IDS deployed correctly? Find out quickly and easily by testing it with real-world attacks from CORE IMPACT. Go to http://www.coresecurity.com/index.php5?module=Form&action=impact&campaign=intro_sfw to learn more. ------------------------------------------------------------------------
