Intrusion Tolerance - Security's Next Big Thing?

An anonymous reader writes "DARPA's OASIS program consists of more than 20 research projects in intrusion-tolerant systems. The basic idea is to concede that systems will be penetrated by malware and hackers, but to keep operating anyway. Other projects take a wide variety of technical approaches to providing intrusion tolerance. MIT's Automatic Trust Management uses models of trust to choose from a variety of ways to achieve system goals; Duke/MCNC's SITAR (Scalable Intrusion Tolerant Architecture) adapts tricks from fault-tolerant systems and distributes decision-making; BBN-Illinois-Maryland-Boeing's ITUA employs unpredictable adaptation. Shutting down the military while waging war is not an option, but the idea of continuing to operating critical defense systems even after known penetration by hostile hackers or damaging worms will take some getting used to."

Comments

BIological Systems

[PktLoss]

I think it is great that something like this is being looked at. Every biological system on the planet works on the same principal, yes, the system will be attacked, keep functioniong, and attempt to regain controll.

I think an interesting option for powerfull machines would be to 'fall on the sword' if complete failure was immenent.

Re:BIological Systems

[ceep]

The biological model is an interesting parallel, but we should also look at the failings of the biological model -- within your body, you are still a big monoculture, so once whatever foreign matter is in, it won't encounter anything radically new.

Intrusion tolerance, IMO, is just a subset of fault tolerance -- something failed to let the intrusion happen. So how do you tolerate that sort of fault?

1. reduce interdependency and single points of failure. If everything relies on the firewall box, and the firewall box goes down, then everything is down, even if everything else wasn't compromised. This is a failing of the biological model -- there are lots of lines of defense, but what happens when something goes straight for the heart? The brain? The spleen? A fault-tolerant system can't have a single point of failure.
2. just say "no" to monoculture. This should be a given in redundancy and fault tolerance, but often isn't. So your firewall is a linux box, and it gets hacked, but that's OK because you have another firewall. Oh wait, it's a linux box too, so it will fail in the same manner. This is not good intrusion tolerance, because your intruder can duplicate his or her (or its) past actions -- more of the same probably won't even slow him/her/it down much.
3. spread stuff around. This usually happens anyway because of load balancing, but couple this with #2 (reducing monoculture) and you'll really slow down an attacker, especially if you can make the separations transparent from the outside.
4. be vigilant! There's no replacement for the human element; hire somebody (or a team of somebodies) to do nothing but spend all day logged in to critical machines and make sure that nothing out of the ordinary happens. This is another failing of many security models -- people think that they can replace people with machines, but machines are easy to fool -- well-trained people are harder to fool, and the combination of the two (since they are fooled in different ways, see #2) is a lot harder to get around.

A good fault-tolerant system will have multiple layers that fail in totally different ways. This will thwart most automated attacks, since they tend to exploit a single, known vulnerability and won't be equipped to respond to another, totally different layer. If the layers are different enough (say a *nix-based firewall behind a Windows-based firewall), most attackers will be so thrown off that they will (at the very least) have to spend a significant amount of time trying to figure out what to do next. This buys you time to realize what's going on and stop it. Couple this with a very low interdependence, and an attacker can spend a lot of time breaking in to something that may be of little or no use to them.

Intrusion tolerance? You betcha -- this acknowledges the fact that there's no such thing as failsafe security, but takes advantage of a wide variety of options, which won't fail similarly, to slow down attacks and give administrators time to see what's going on and stop it.

Isn't this all obvious though? It seems like it when you read it, but the 4 concepts noted above are very often ignored (to varying degrees). Especially #2; this is the hardest because it means hiring a *nix geek and a Windows geek and a Cisco geek and maybe a couple of other ones as well, and no one wants to spend that kind of money. So instead, they get a guy or gal who only knows one system, so everything lives or dies on the failings of that system. Or even worse, they hire a whole team of guys and/or gals that all agree to use the same platform, for simplicity's sake. Bad! Bad! Remember the scale:

More Secure...................Less Secure
_________________________________________
Less Convenient...........More Convenient

Eh. Talking's easy...

--
eep

Analogy

[unixwin]

What has to be understood is that a compromised system, if part of a larger group of compro & non-compro systems can have a lot of undesirable consequences. In a Corporation network of say 150 servers a couple broken in boxes serving as open relays, ftp/warez sites or just sniffing around do not necessarily have to bring the whole Company down for a day, pulling the plug on them is always an option.

However if your servers/farms are crunching numbers for a Satellite recon or is running a battlefield communication center then your not quite sure how it would behave. A lot of modelling and discussions will go on about this, but some of these problems (of data consistency) have already been handled previously in Computer Science... so its not that big a deal.
It will I guess be like one of those "decisions" a battlefield commander takes, of how much he trusts the intel he is getting and how he wishes to proceed and are the risks acceptable.
Similarly the network/systems ppl will be making choices whether they can live with this intrusion or not...how best to handle it without stopping the grid.

That's what war is all about!

[dtolton]

Shutting down the military while waging war is not an option, but the idea of continuing to operating critical defense systems even after known penetration by hostile hackers or damaging worms will take some getting used to."

What do they think the military goes home when someone gets killed or they find out there might be a spy? That's why our military security is completely segmented. The whole concept of need to know basis, is the understanding that information will fall into the wrong hands, you just want to minimize how much information can fall into the wrong hands when someone or something is compromised. That computers, especially military computers would follow this highly pragmatic principle shouldn't come as much of a surprise.

Prior Art?

[Anonymous Coward]

" concede that systems will be penetrated by malware and hackers, but to keep operating anyway"

Hasn't this always been the strategy of Windows? Now if they could just finish implementing that second part...

Just My .02 USD

[Sam Nitzberg]

In general, I don't like the idea of making a concession that malware will have to be operating in a given computing environment (as stated above), and to think otherwise would simply be incorrect. OK, Windows environments may be an obvious exception ;-)

I would prefer to consider that (at least from my own philosophical viewpoint), that you can construct systems with defined patterns of behavior, even when "malware" is introduced.

From one of the links referenced above :

Successive levels in the hierarchy are linked by refinement mappings that can be shown to preserve properties of interest. This project will apply this technology to intrusion tolerance properties.

This harkens back to enforcement mechanisms (Biba Integrity Model, No Read Up, No Write down policies, Models for descriptions of multi-level secure behavior, etc...). (Aside: Amoroso's book is an excellent reference)

What this alone tells me (I didn't read all the blurbs, articles, and briefings), is that we are discussing mappings (mathematical functions), and properties (which can be mathematically tested for by use of a logic or algebraic system).

At a glance, I am thinking of some of the issues in formal methods, proven-secure-O/S kernels, and other high-reliability software engineering methods for [secure] systems.

I like the idea that mathematical theorem provers can be applied to any system so defined.

Some basic issues do arise for practical application :

- Theorem - proving aspects mean very precise use of functional requirements and mathematical specification for system behaviors. (Also, special talent and additional manpower is necessary. Also, mis-applications of the tools used, or introduced human error in the test process can subvert the efforts)

- This should be applied (I believe) to systems-of-systems and their behaviors. The systems that your system interacts with would have to had similiarly rigorous analysis and design.

- There is (I believe) a trend in military computing towards commercial, and less custom, software development. Long-term, where will the actual development of such systems be funded (beyond the initial R&D stage).

- The use of analysis of pre and post conditions in the executing environment (to ensure that violations of the underlying security policy are not permitted) is not a new concept. While I am not saying that this is an intrinsically ecessary mechanism for these methods, most current system lack such an approach, and there may be fundamental computer security issues present by the nature of the software development environment. If these methods are used, it is still highly desirable to design systems with security in mind regarding their handling of all data, traffic, and O/S vulnerability issues.

I only took a brief look at the material, but these are some thoughts. I also think that the effort itself is very worthwhile, and potentially of value. Also, looking at Dr. Lulu's credentials, there is no naivite in his software background; the basic tenents can't just be shrugged off.

Sam Nitzberg
sam@iamsam.com
http://www.iamsam.com

Re:Repeat after me...

[Monkelectric]

...this new mantra of security.

This replaces the old mantra right? "I refuse to patch, for patches deny faith, and without faith I am nothing." (Douglas Adams)

Similar idea to another group

[pioneer]

This is similar to research being done at MIT in the Computer Architecture Group by Martin Rinard and his graduate student Brian Demsky. They are building and researching ways to automatically detect and repair data structure errors so that if a programs data structures get corrupted their tool will repair the heap so the program can keep running.

There was related work done like this back in the day at AT&T but Rinard and Demsky have introduced automatic repair which, as you might imagine like this security idea, is scary to some people. Imagine a program that would have crashed due to some bug or malicious data mangling, now kept running by a tool... But the tool chooses the repair actions based on heuristics and specifications by the developer... takes some getting used to!

All of this stuff falls under fault tolerance... its pretty crazy to look at what the AT&T/Lucent Phone Switches do when they fail... they try a million different things to keep operating no matter what happens...

Re:BIological Systems - Scares me!

[dekashizl]

Every biological system on the planet works on the same principal, yes, the system will be attacked, keep functioniong, and attempt to regain controll.

I don't know about you, but my neck hairs bristle at the shift of computer systems into the biological (model) realm. I am well aware that biological systems function well in the face of a variety of offenses.

But they (biological systems) also autonomously evolve, compete strongly, and often get wiped out. And when they do too well, they have the tendency to consume all resources, pollute, and then die out or reinvent themselves.

We (humans) are a biological animal. Let's be careful building something that will compete with us. The potential dangers of this scenario have been played out in Terminator and countless other sci-fi epics. Self-aware entities fight for their survival and the survival of their species/genes.

You might say "but we control the technology", but in fact the next generation of computers will control us. Digital Rights Management (DRM) is in effect our surrendering of our rights to machines. As more of our survival becomes dependent on machines (as has been increasing at an exponential rate recently), this means our rights of survival are out of our hands. Think of DRM as the Declaration of Independence, but in reverse -- well, we had a nice run there for a couple hundred years! But I'd rather be a heavily-taxed under-represented colonist of a foreign empire than a farm animal to machine masters any day.

I don't mean to rant tinfoil hat conspiracy nonsense, and it's important to secure our systems from collapse, but let's not be so quick to push ourselves toward slavery just yet. I think this (self-aware networks) is an area that is as important as nano/biotech to watch out for, and it's far more likely that we become totally enslaved to technology than that we all get turned into gray goo.