IDS mailing list archives
Re: Cisco IDS 4250 vs Sourcefire IS3000 + RNA Sensor
From: byte_jump <bytejump () gmail com>
Date: Fri, 14 Oct 2005 15:05:28 -0600
On 10/13/05, Tim Holman <tim_holman () hotmail com> wrote:
Hi Jonathan, Wouldn't you rather block bad traffic, rather than detect it? Most companies are moving away from IDS as a protection mechanism, because: 1) It only detects, and doesn't effectively block intrusions 2) Problems with false positives, as by using pattern matching signatures, there is always a chance that these patterns also appear in valid traffic
Problems with false positives are inherent in either system. An IPS is simply an inline IDS with signatures to match. In fact, I think IPS suffers the most in this regard. Every IPS I have seen touts its "0day" detection and prevention, but in reality are so neutered as to be nearly ineffective against anything other than Code Red. If we're going to talk false positives - and both systems have them - I'll take one that I can look through and sift out than one that gets the C-suite upset because it blocked some mission critical app, thus crying wolf and causing the C-suite to second-guess me and my budget. Reality is that, while IDS is "dead", IPS is a eunuch.
3) Management overheads. An IDS can only be a reasonably effective prevention method if there is someone on hand 24/7 to monitor logs and take immediate action on intrusions. Even then , the intrusion has got in, as admins very rarely use the active blocking features of an IDS (namely sending RST packets to kill connections, or modifying upstream ACLs), as these are too likely to have an effect on valid traffic
Again, baloney. What you claim is true if an IPS/IDS is your sole defense against intrusion. If I can't get host-based security in place and my network is so brittle that an attack bypassing my IPS is a successful one, I'll hang it up. If my IDS detects an attack against my Apache server, but doesn't block it, I'm not sweating it. My Apache server is running on OpenBSD or Gentoo with GRSEC/PaX, has mod_security installed, is in a chroot jail, has systrace policies, etc. I'm not too concerned about something that my IDS detects getting in. I'm more concerned about something that my IDS doesn't detect, and IPS suffers from the same problem - don't fool yourself.
4) There is absolutely no protection for rate-based attacks (SYN, TCP, UDP floods)
Firewall.
5) Without maintaining a L3/4 connection/state table, there is no way an IDS can be truly stateful. 100% statefulness means that everything from the initial SYN to the final RST/FIN packet of a connection is stored in a connection table. This requires the device to be INLINE, and operating at L3. This is the only way a protection device can provide effective defence against L3 attacks. An offline IDS cannot do this.
Yes, it can. NFR has been doing this for years.
I would recommend looking at IPS products instead, so something that you can postion inline and get immediate value from. If you feel the Cisco IDS is getting a little tired, then an IPS will also help take the load off it, by getting rid of Internet white noise, providing additional firewall filtering, and also defence against rate-based attacks. A true IPS will focus on defining what is GOOD traffic, and assuming all else is BAD (and dropping it). By doing this, zero-day attacks can be virtually be eliminated, as they all ultimately rely on abuse of a valid protocol in the hope of slipping past your protection mechanisms and onto your network. This works quite well in conjucntion with an IDS, that focuses on searching traffic for badness. Replacing like for like (IDS for IDS) is not going to give you much value, and even the market analysts are recommending against it. IDS isn't dead. Far off it, but use it for what it's good for - DETECTION and FORENSICS, and not as a device that can insure your network against rate-based and zero-day attacks.
Firewalls, segmentation, and most importantly, host-based protections are much more effective here than IPS is. How's my fancy IPS going to detect that SQL injection attack against my SSL web server? Oh, that's right - it can't. What about custom encryption? What about CANVAS or Hydrogen (http://www.immunitysec.com/products-hydrogen.shtml)? Host-based protections are your only hope here. ------------------------------------------------------------------------ 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.securityfocus.com/sponsor/CoreSecurity_focus-ids_040708 to learn more. ------------------------------------------------------------------------
Current thread:
- Re: IDS and Spywares, (continued)
- Re: IDS and Spywares Gadi Evron (Oct 07)
- Re: IDS and Spywares Dhruv Soi (Oct 11)
- Re: IDS and Spywares Jay Archibald (Oct 12)
- Re: IDS and Spywares Tim Holman (Oct 14)
- RE: IDS and Spywares Andrew Plato (Oct 07)
- Re: IDS and Spywares Eric Grejda (Oct 11)
- RE: IDS and Spywares Desai, Deepen (Oct 11)
- Re: IDS and Spywares barcajax (Oct 11)
- Cisco IDS 4250 vs Sourcefire IS3000 + RNA Sensor Jonathan Gauntt (Oct 12)
- Re: Cisco IDS 4250 vs Sourcefire IS3000 + RNA Sensor Tim Holman (Oct 14)
- Re: Cisco IDS 4250 vs Sourcefire IS3000 + RNA Sensor byte_jump (Oct 18)
- Re: Cisco IDS 4250 vs Sourcefire IS3000 + RNA Sensor Frank Knobbe (Oct 18)
- Re: Cisco IDS 4250 vs Sourcefire IS3000 + RNA Sensor Jason (Oct 18)
- Re: Cisco IDS 4250 vs Sourcefire IS3000 + RNA Sensor Jason Haar (Oct 18)
- Re: Cisco IDS 4250 vs Sourcefire IS3000 + RNA Sensor Joel Esler (Oct 19)
- Re: Cisco IDS 4250 vs Sourcefire IS3000 + RNA Sensor Teemu Schaabl (Oct 18)
- Cisco IDS 4250 vs Sourcefire IS3000 + RNA Sensor Jonathan Gauntt (Oct 12)
- RE: IDS and Spywares vipul kumra (Oct 12)
- RE: IDS and Spywares Omar A. Herrera (Oct 13)
- RE: IDS and Spywares Matt Jonkman (Oct 14)
- RE: IDS and Spywares Omar A. Herrera (Oct 14)
- RE: IDS and Spywares Matt Jonkman (Oct 14)
- RE: IDS and Spywares Omar A. Herrera (Oct 13)