Hi VT, I strongly believe that replay tools are NOT an effective way to test an IPS:
1) Replay tools are an unfair way to compare vendors. There is no measure as to the speed at which an IPS vendor responded to the original vulnerability. These .pcap files have been around for months or even years, giving plenty of time for vendors to catch up and write signatures to stop them. It's all very well having an IPS that responds favorably to a replay tool, but if certain signatures took days, weeks or even months to write, then this is not a fair way to compare device A with device B. It can be difficult to get hold of, but try and get the 'time to respond' stats from your proposed IPS vendor. 2) Replay tools do not test variants. Although the pcap content may reflect a specific exploit, what about all the other exploits that abuse the same vulnerability? For example, the 50+ odd variants of Blaster, Slammer or Code Red? These test tools usually include pcaps for one particular variant only. A good freeware tool to test variations is Metasploit, or if you have spare cash, Canvas is a worthwhile investment. 3) Replay tools do not test ability of a device to withstand volume. When worm/virus outbreaks happen, you don't just get a single packet in .pcap fashion that comes in, trips a signature, and gets blocked. You usually get several million of them. This is where it is important to test any rate-based features of the device. Also make sure these rate-based features don't block valid traffic. Plenty of freeware tools available - Apache Benchmark, nmap, Nessus, hping2 and a SYN Flood tool called Juno. What's more, these tools do not rely on .pcaps, so are a lot more real world. Be warned that replaying an identical pcap several million times is not an accurate way to rate-test, seeming all L2/L3 information is identical in each packet (eg no change in SEQ). Devices that are good at DDOS tend to be just as good at withstanding sudden, large propagation of worms. 4) Replay tools do not test IPS avoidance. Well, you may get vendor-supplied pcaps like blaster_with_fragments.pcap, but there are so many other ways to evade an IPS, and can you be sure that the vendor supplied .pcap is a reflection of real world traffic? Get hold of fragroute, tcpsic, plus nessus has some good evasion options. 5) Replay tools do not test zero-day protection. This is the fun bit. How do you test a network IPS protects you against the shape of things to come? If you have a research team that can generate signatures to protect you quickly, then great. But there's still a window of opportunity during which your security can be breached. If an IPS is firing back events such as Sasser.W32/A blocked, or Code.Red.B.W32/Z, then chances are, it's not an anomaly based system that will give you much in the way of zero-day protection. But if it's firing events like 'CIFS Field Too Long' or 'HTTP Header Contains Illegal Characters', then this is indicative of the machine having good anomaly/zero-day procetion, rather than specific signatures for specific pre-historic viral events... ;) IPS testing is a big task, and needs big tools - to do things properly, take a look at the NSS testing suite, for example - http://www.nss.co.uk/utm/appendix_a/appendix_a.htm In conclusion (I hear sighs of relief...): * Replay tools cannot be solely relied on to test an effective IPS * Think about what you want your network IPS to do - content-based checks are important, but equally as important are access control and rate-based ability. * A network IPS will never provide 100% perimeter protection. Always invest in extra security layers, especially host-based, to ensure that anything the IPS lets through does not cause problems * If you buy an IPS on the merits of tcpreplay results, you risk being hit with a zero-day threat or DoS condition, and losing your job. * Treat any vendor that promotes testing with a replay tool with caution (I learnt the hard way..) Hope this helps, Regards, Matt --- Arun Vishwanathan <[EMAIL PROTECTED]> wrote: > Hi VT, > > I have used IDSInformer myself for testing and it is > a very good > product. There is a similar free tool (but lacks > certain features) > called Tomahawk which was released by Tippingpoint > some time back. > (http://tomahawk.sourceforge.net/) > > The working of these tools is very simple. You have > to assign two > interfaces. The tools consider one interface as > "client" and other > interface as the "server". The PCAP can be easily > split into two parts, > client traffic and server traffic. Consider the > following simple packet > sequence (A and B are IP addresses). > > 1. A -> B SYN (client) > 2. B -> A SYN-ACK (server) > 3. A -> B ACK (client) > > Packet 1 is first sent out on client interface. The > packet is expected > to arrive on interface 2 within a certain timeout. > On receipt of packet > 1, packet 2 is sent out on interface 2. Then packet > 3 is sent out on > interface 1 on receipt of packet 2 and so on. They > make the IDS believe > that it is seeing a real traffic situation. > > In informer, you can change the MAC, IPs, Sport, > Dport of the packets. > In tomahawk you can only change the IPs at present > but if you want to > you can easily modify the code as its very simple. > There is no need to > configure any networks on the interfaces etc. Infact > the IPs, MACs can > be spoofed because it really doesn't matter. > > Tomahawk has one limitation that it cannot test a > Layer 3 device because > it lacks support for specifying the source gateway > MAC and Destination > gateway MAC. It can test only Layer 2 devices. > Informer can be used in > both L2 and L3 situations. > > In my opinion, both tools are great. I have used and > am using both tools > extensively. Informer also has an evaluation > version. You can download > it and try for yourself. For both the tools very > little configuration is > required. > > Hope I was able to clear some of your doubts. > > Regards, > Arun > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] > Sent: Sunday, November 06, 2005 6:11 AM > To: [EMAIL PROTECTED]; > [email protected] > Cc: Tony Haywood; [email protected] > Subject: RE: Intrusion Prevention requirements > document > > This sounds like a very viable solution that will > allow for testing. I > assume that it replays both the stimulus and > response of any > conversation and does not "fingerprint" the packets > at any layer with > the host OS TCP/IP stack (e.g. change of window > size, TTL, etc)? Does > the product automatically adapt to replay source and > destination traffic > based upon reading a libpcap file or do you have to > configure the > networks per card? > > Has anyone else used this or a similar product in > their testing or other > security product tests? What issues did you > encounter? > > Thanks for the feedback, > -VT > > > > One of the ways that you could test safely is by > using something like > > Traffic IQ Pro or a similar product. It is a > stateful traffic replay > tool > > and can be used to test any inline or packet > monitoring device. > > > > The product uses two network cards and so the > library of over 700 > normal and > > threat traffic files can be replayed statefully > without the need to > connect > > to a live target system. This allows for live > production systems to be > > testing for the correct configuration really > quickly and easily. > > > > I have been involved in working in this area for a > number of years now > and > > my previous company was Blade Software where I > developed IDS Informer > and > > Firewall Informer to provide similar testing > capabilities. > > > > Information on Traffic IQ Pro is available below > should you want to > take a > > look. > > > http://www.karalon.com/Karalon/TrafficIQ/TrafficIQ.htm > > > > Working with testing labs and a number of security > and networking > vendors > > has enabled Traffic IQ Pro to be a really useful > tool for anyone who > wants > > to check the configuration of their firewalls, > IPS, IDS, routers, > switches > > etc and see how those devices perform under > different scenarios. > > > > Tony > > > > Tony Haywood > > www.karalon.com > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] > > > Sent: 29 October 2005 20:40 > > To: [email protected] > > Subject: Re: Intrusion Prevention requirements > document > > > > Another question for everyone, > > When you brought in each vendor for evaluation, > did you configure a > test > > network for them or did you use your production > network? My 1st > concern is > > keeping my job :o) If I test in production, I > could impact production > > traffic. If I don't test in production, how can I > best ensure that I > won't > > have problems with custom applictions, older IP > stacks which could be > an > > issue if RFC compliance checks are done, etc. > > The vendor answer is always, "don't turn on > blocking and just > monitor." Is > > that a reality? I'd like some testimonials to > this and some real > life > > instances of what has been done from unbiased > sources. > > > > Thanks, > > > > VT > > > > > > > All, > > > > > > I work on a team that manages signature and > behavioral based > intrusion > > > detection systems today. We have been tasked > with reviewing IPS (or > > > > whatever vendor name acronym you prefer) in '06. > Our normal process > > === message truncated === ___________________________________________________________ To help you stay safe and secure online, we've developed the all new Yahoo! 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