IDS mailing list archives
Re: ForeScout ActiveScout
From: Brent Stackhouse <brentstackhouse () yahoo com>
Date: Fri, 7 Jan 2005 22:10:51 -0800 (PST)
Gadi, Thanks very much for your detailed response. I understand their definition of 100% accuracy but it still begs the question as to how they make the initial determination of what to track or not. Surely they don't send their crafted data on every single connection to see if it comes back. Their web site states that ActiveScout is looking for recon activity so some threshold or "trigger" must exist for them to differentiate recon from legitimate traffic. Their site also states that they're not signature based. Again, if they have some sort of logic based on thresholds (x amount of TCP packets per minute from the same source IP, etc.), it sounds like a signature to me. At least I know that Cisco, ISS, etc. all have threshold-based signatures in their IDS products. All that aside, I saw the results of a SuperScan port scan that included a bunch of junk caused by ActiveScout. I would think that feeding an attacker a bunch of info that leads them to believe that you're really vulnerable is not a great idea (like open SunRPC ports, NetBIOS, etc.). I want less attention, not more. I suspect that anything out-of-the-ordinary would perhaps cause more attention. This is sort of a honeypot idea gone berserk. Instead of one host appearing vulnerable, all of your hosts appear vulnerable. Anyway, it doesn't sound like it buys much, if anything, over "traditional" IDS/IPS. Thanks, Brent --- Gadi Evron <ge () linuxbox org> wrote:
Brent Stackhouse wrote:Hello,Hi. I tested ActiveScout, so I'd like to respond. Before hand, allow me to say that although I've used different IDS/IPS products extensively, and tested many of them (companies always want to test them on our network, being, according to comparisons I made so please don't take my word for it, one of the most attacked networks in the world). I am by no way close to being an IDS/IPS expert nor was I ever involved in development of such, save for writing signatures and a good understanding of theory.Just a quick question on ForeScout ActiveScout astowhether anyone out there has used/eval'd it. I'm working with a client that is using an old version (2.7.x, I believe), is considering an upgrade, andI'mnot sure it's worth the time and effort.The upgrade is extremely easy and quick (or should be, and was for me). Cost vs. benefit. I don't see why not. Go for it, there are improvements.They claim 100% accuracy which we all know issilly. Usually, I'd be the first to agree. Still, in this case, they claim right. How come? Basically, as far as I understand it, they say: "we wait for you to check us out, and then we watch you. If you come back and try something evil, we will know it is you and that you are trying it". Now, I still don't like "100%" claims regardless, but under this definition, they are right. They don't catch 100% of all attacks, but it is "virtually impossible" for them to make a false positive if all things are even (no bug or weird network issues), and things are usually even. In my personal experience, false positives COULD rarely occur with weird network issues (and that's not their fault), but in my experience ActiveScout will then MONITOR an IP it shouldn't, but it wouldn't block it. What's the harm in that?Their whole methodology is based on an attackerusingrecon in advance of an attack and that the recon activity is detectable enough to start interfering with it.Yep.From what I can gather from ForeScout's literatureandthe management console of the app itself, whenit'sable to run at all (Java-based, slow as dirt),this It works fine for me. Maybe your machine is slow as dirt. I do agree it has a rather old look. I personally really dislike it, but it's just a GUI.product sits on the outside of the perimeter andlooksfor suspicious traffic via a span session. Whenitdetects scans or similar recon activity, it canbothsend back spurious information to the source IPandupdate a firewall to block it. It seems to track attacking IP's based on the spurious info italreadyfed them.It's really an incredible concept (if we leave the product aside for a second). They feed the probing (not attacking) user false data. If that IP returns, it is a bad guy. If another one returns with the false data - it is the same guy, and he is obviously evil. Thresholds can be set, nobody said that if you went to port 445 instead of 443 twice, you'd trigger it. Very configurable. Plus, if I remember correctly, there are thresholds for preventing it from getting DDoS'd as well. As to blocking - you don't have to let it use the FW. It can send resets. They have a pretty neat (yet old looking) picture of the world, too. It really helps out with the budget people.Also, this version doesn't seem to track SMTP andDNS,two of the most oft-attacked protocols out there.Why should it? It is not a regular IDS or IPS and in no way comes to replace them. If it sees a bad user doing something that would demand him being "marked" - which can be any number of things (but not that many really - there aren't THAT *many* ways to gather recon), and he tries something against SMTP... The user may also attempt something horizontally (against one machine on many ports) or vertically (against many machines on one port), etc.Having run one or two firewalls and NIDS setups myself, I'm not clear on the benefit of this beast compared to either inline IPS or IDS plus firewall blocking (or a firewall and patched servers, whileI'mgoing that way).Simple benefit is, you can put it on your network, not monitor it at all, and it would do it's job. More complicated benefit is, it will catch attacks, new worms, etc. regardless of there being a signature for it, and without (at least shouldn't be) any false positives (under their definition).Stupid question - if my perimeter devices,includingDMZ servers, are patched, why the heck would Iwant to So? What if it is a 0day? What if there is no patch yet? What if it is a port scan? What if it is any number of other things? (some of which you may not personally care about)send back _any_ data to an attacker? I guess ifyourservers weren't patchable for some reason, maybeyou'dwant to fake that they really are. Um, okay. Probably better ways to handle that. I wouldthink It's an issue of if you want to run an honey pot and look all happy and shiny to the attackers, or not. It isn't necessarily about their product.that if my perimeter is properly locked-down, I'm quite happy for an attacker to scan it and figurethatout for themselves - assuming they get much of ascanpast IPS/IDS/firewall.It isn't a regular IPS.What am I missing? Thanks for the feedback.No technology is perfect, and they seem to learn and evolve with time as expected. It isn't for everybody, and trusting it is not a simple issue for a paranoid mind, but hey - that's the same with any IPS or anything that blocks automatically. If you already have it - upgrade, why not? If you don't I'd strongly recommend it, but not if what you want is an IPS with shiny and cool signatures. Now, I don't speak for ForeScout, so I may have things wrong. All I am is a guy who tested the product. Try seeing what the point of this product it. Before I got it, I really didn't like it and kept expecting something different from it.. heck, I even blamed it for some DDoS, but it isn't a DDoS mitigation tool, is it now? Use this chance to see how it works, and reach your own conclusions. :) Gadi Evron.
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Current thread:
- ForeScout ActiveScout Brent Stackhouse (Jan 07)
- Re: ForeScout ActiveScout Gadi Evron (Jan 08)
- Re: ForeScout ActiveScout Brent Stackhouse (Jan 08)
- Re: ForeScout ActiveScout Gadi Evron (Jan 10)
- Re: ForeScout ActiveScout Brent Stackhouse (Jan 08)
- <Possible follow-ups>
- RE: ForeScout ActiveScout Carey, Steve T GARRISON (Jan 08)
- Re: ForeScout ActiveScout dywzh dywzh (Jan 10)
- Re: ForeScout ActiveScout Brent Stackhouse (Jan 10)
- Re: ForeScout ActiveScout Gadi Evron (Jan 12)
- Re: ForeScout ActiveScout Erik F (Jan 12)
- Re: ForeScout ActiveScout Gadi Evron (Jan 08)