not long after my last post on the subject of KHOBE, david harley posted a collection of links about it on the AMTSO blog and one in particular caught my eye. specifically the one by ralf benzmüller on the gdata blog.
what's interesting about it is that it shows the KHOBE media circus in a new light that i think deserves a lot more attention.
it appears that there was a very good reason for the sensationalistic headline that matousec used when announcing their research (the reference to an 8.0 earthquake sounded positively cataclysmic) - they're looking to cash in. they're expecting the companies they claim are affected to fork out a ton of cash for the paper containing the details (and they're offering their services to those companies too). how much is a ton of cash? the combined amount for all companies will apparently be in the 6 figure range (ka-ching!). on top of that their correspondence is anonymous (what?!, why use anonymity in this context?) which, when taken with the money grab they're attempting and their sensationalism in announcing the attack, takes what once looked like just an irresponsible action (that happens altogether too often in security research circles) and makes it seem downright shady.
whichever way you look at it, if ralf benzmüller's account of events is accurate then it's clear that matousec's interests do not lie in helping the community become more secure and i can only hope the majority of the companies named in their initial release avoid the kinds of back-alley dealings these mustache-twirling individuals seem to have in mind.
Showing posts with label KHOBE. Show all posts
Showing posts with label KHOBE. Show all posts
Saturday, May 15, 2010
KHOBE extortion
not long after my last post on the subject of KHOBE, david harley posted a collection of links about it on the AMTSO blog and one in particular caught my eye. specifically the one by
understanding KHOBE
there's been quite a lot of press given to the research surrounding KHOBE this week, and while the coverage on the normal anti-malware blogs i follow was quite good, coverage outside that community left something to be desired (accuracy? comprehension?).
to start with, KHOBE is not so much an attack as it is a technology. KHOBE stands for Kernel HOok Bypassing Engine. it's technology developed by matousec to do exactly what that name suggests - bypass kernel hooks. it does this with a technique that matousec calls argument switching but which has in the past been called a time-of-check-to-time-of-use attack (or TOCTTOU attack; see this post on the eset threatblog).
this sort of attack is an active countermeasure, meaning a piece of malware implementing this attack has to be active in memory in order for attack to be performed. this means, first and foremost, that in order to mount this sort of attack the malware already has to be able to get past traditional scanning technologies without using argument-switching, since they examine the program before it's allowed to execute and become active.
as such, the anti-malware techniques that argument-switching is a countermeasure for are behavioural techniques (including, but not limited to certain self-defense techniques that anti-malware products use to prevent being shut down by malware that becomes active). by switching the contents of memory after a chunk of code has been checked for potentially malicious intent but before it's passed to the system to execute, this attack manages to prevent behavioural detection/prevention techniques from seeing the code that is actually going to be executed and in that way constitutes a kind of stealth that works against behavioural techniques (though it only works against behavioural techniques that are implemented in a particular way - using the particular kernel hooks that KHOBE was designed to bypass).
behavioural stealth is interesting at least so far as it demonstrates some of the limits of behavioural techniques to protect systems from attack (all techniques have limitations). from a strategic point of view, once a piece of malware is able to execute it's already passed every opportunity you had to prevent compromise outright - at that stage the only thing left is to contain the damage using behavioural techniques and/or sandboxing. behavioural stealth could clearly render containment by behavioural blocks ineffective (again, if it's implemented using the kernel hooks in question) and might even bypass the sandboxing technology, depending on how it's implemented.
although the attack has apparently been known about for some time (much longer, it seems, than the folks at matousec realized), it hasn't yet been used. however, that may now change as the current threat ecosystem is much different from when TOCTTOU was originally discussed. matousec has raised the attack back out of the depths of obscurity and there are now any number of computer criminals out there who would be more than willing to take matousec's research and use it for their own gains (much like what happened to eEye's bootroot research). this is the risk one takes when publishing attack research for the world to see, so you have to weigh your options very carefully to see if it's really worth arming the bad guys. and of course don't just follow full disclosure dogmatically simply because it seems like that's what everybody else does - as emerson said "a foolish consistency is the hobgoblin of little minds".
to start with, KHOBE is not so much an attack as it is a technology. KHOBE stands for Kernel HOok Bypassing Engine. it's technology developed by matousec to do exactly what that name suggests - bypass kernel hooks. it does this with a technique that matousec calls argument switching but which has in the past been called a time-of-check-to-time-of-use attack (or TOCTTOU attack; see this post on the eset threatblog).
this sort of attack is an active countermeasure, meaning a piece of malware implementing this attack has to be active in memory in order for attack to be performed. this means, first and foremost, that in order to mount this sort of attack the malware already has to be able to get past traditional scanning technologies without using argument-switching, since they examine the program before it's allowed to execute and become active.
as such, the anti-malware techniques that argument-switching is a countermeasure for are behavioural techniques (including, but not limited to certain self-defense techniques that anti-malware products use to prevent being shut down by malware that becomes active). by switching the contents of memory after a chunk of code has been checked for potentially malicious intent but before it's passed to the system to execute, this attack manages to prevent behavioural detection/prevention techniques from seeing the code that is actually going to be executed and in that way constitutes a kind of stealth that works against behavioural techniques (though it only works against behavioural techniques that are implemented in a particular way - using the particular kernel hooks that KHOBE was designed to bypass).
behavioural stealth is interesting at least so far as it demonstrates some of the limits of behavioural techniques to protect systems from attack (all techniques have limitations). from a strategic point of view, once a piece of malware is able to execute it's already passed every opportunity you had to prevent compromise outright - at that stage the only thing left is to contain the damage using behavioural techniques and/or sandboxing. behavioural stealth could clearly render containment by behavioural blocks ineffective (again, if it's implemented using the kernel hooks in question) and might even bypass the sandboxing technology, depending on how it's implemented.
although the attack has apparently been known about for some time (much longer, it seems, than the folks at matousec realized), it hasn't yet been used. however, that may now change as the current threat ecosystem is much different from when TOCTTOU was originally discussed. matousec has raised the attack back out of the depths of obscurity and there are now any number of computer criminals out there who would be more than willing to take matousec's research and use it for their own gains (much like what happened to eEye's bootroot research). this is the risk one takes when publishing attack research for the world to see, so you have to weigh your options very carefully to see if it's really worth arming the bad guys. and of course don't just follow full disclosure dogmatically simply because it seems like that's what everybody else does - as emerson said "a foolish consistency is the hobgoblin of little minds".
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