Friday, December 30, 2016

thoughts on "In Search of Evidence-Based IT-Security"

Christopher Soghoian brought to my attention a video of a talk by Hanno Böck at the 33rd Chaos Communication Congress. in it Hanno puts forward the claim that IT security is largely science-free, so let's follow a staple of the scientific process - peer review.

Hanno introduces himself as a journalist and hacker and says that he prefers to avoid the term "security researcher" and that he hopes the audience will see why.  for those who are relatively well versed in the field of anti-malware it should definitely become obvious why he prefers to avoid that term and i'll return to this near the end.

Hanno is a skeptic, and far from the only one, his talk ultimately expresses the same sentiments that are now common-place in the perennially misinformed information security community. the difference is that Hanno has found a novel way of expressing them, couched in scientific jargon and easily mistaken for insight. he spends altogether too long and dives too deeply into the medical analogy upon which computer viruses and by extension anti-virus software is named. the analogy has long been recognized as deeply imperfect and limited. that's why, in reality, there are relatively few references to this analogy in the anti-malware field other than "computer virus", "anti-virus", and "infection" (all three of which date back virtually to the beginning of the field). his call towards the end of his talk for blinded or even double blinded studies, aside from being prohibitively expensive to perform, seem to cling to this medical paradigm in spite of the fact that the subject of such experimentation (ie. the computer, since we're interested in whether AV can prevent computers from becoming compromised) cannot be psychologically influenced by knowledge of which (if any) anti-virus is being used.

when he FINALLY leaves the topic of medical science to return to security products (about 14 minutes into his half hour talk) he harps on the absence of one very particular kind of experiment being performed on security products - what he calls a randomized controlled trial. it turns out this is a hold-over from his preoccupation with medical science. when Hanno says that IT security is largely science-free it is the absence of this particular kind of scientific experiment that he is referring to, but that doesn't actually make it science-free because science has a variety of different ways to study and experiment on things that aren't people.

there is in fact good scientific evidence for the efficacy of anti-virus software and it's provided by none other than Microsoft:

now it's true that this is data is from an observational study and that it only shows correlation rather than causation, but that's not the end of the world. observational studies are still science. showing correlation may not be definitive evidence but it's still strong evidence, especially considering the scope of the study (hundreds of millions of computers around the world out of a total estimated population of 1.25 billion windows PCs). in this particular case A may not be causing B but B definitely can't cause A and if anyone can think of a confounding variable that might be present on hundreds of millions of systems then maybe let Microsoft know so that they can try to account for it in the future.

another source of scientific evidence (oft derided in information security circles because the results don't match experts' anecdata) are the independent testing labs like av-test.org or av-comparatives.org. they eliminate the influence of confounding variables and so are capable of showing causation rather than just correlation. unfortunately Hanno believes their methodology is "extremely flawed". let's look at his complaints:
  • "If a software detects a malware it does not mean it would've caused harm if undetected."
    • this is trivially false. anyone who actually reads the testing methodology at av-comparatives (for example) can find right at the beginning a statement about first testing the malware without the AV present and eliminating any that don't work in that scenario. therefore every sample that is detected by AV in their tests would have caused harm if it had gone undetected.
  • "Alternatives to Antivirus software are not considered." (the talk gives "regular updates" and "application whitelisting" as examples)
    • the example of "regular updates" is frankly a little bit bizarre given Hanno's earlier references to confounders. not controlling for this scenario would actually introduce a confounding variable and make it more difficult to show a causal relationship between the use of a particular AV and the prevention of malware incidents.
    • the example of "application whitelisting" underscores a serious problem in Hanno's understanding of what he's critiquing. application whitelisting isn't an alternative to AV, it's a part of AV. many products include this as a feature. Symantec's product, for example, has what they call a reputation engine which alerts when it encounters anything that doesn't have a known good reputation (which means new/unknown malware, traditionally the bane of known-malware scanning, will get alerted on because it hasn't been seen before and thus no reputation, good or bad).
  • "Antivirus software as a security risk is not considered."
    • when malware exploiting vulnerabilities in anti-virus software is found in the wild then perhaps the test methodologies should be updated to include this possibility. until then, changing the methodology to account for malware that doesn't seem to exist outside a lab has no real benefit.
  • "None of these tests are with real users."
    • again, this would introduce a confounding variable. maybe the lack malware incidents is because of something the user did rather than because of the AV. alternatively maybe the failure to stop malware incidents is because of something the user did rather than because of a failure of the AV. if you want to establish causation you have to control your variables (something our scientifically-minded speaker Hanno should know all too well). does the anti-virus prevent malware incidents? the tests say yes. can a user preempt or compromise that prevention? also yes. is there any prevention a user can't preempt or compromise? sadly (or perhaps thankfully) no. if you want a study that includes users and thus eliminates the ability to establish a causal link between AV use and prevention of malware incidents, see the study by Microsoft, but even with the inclusion of the users it still suggests AV prevents malware incidents.

when Hanno addressed the paucity of scientific papers dealing with security i found myself confused. using Google Scholar to find the most cited scientific papers? surely he doesn't think the realm of security is so narrowly focused that he'll find what he's looking for that way. security is in fact incredibly broad, covering many different quasi-related domains, and looking at a handful of the most popular scientific papers across all of security is in no way representative of the corpus of available works related to any one particular field (like security software). perhaps i'm biased, having previously (in the very distant past) maintained a reference library of papers related specifically to anti-virus, but it doesn't seem like Hanno showed much evidence that he knew how to find evidence-based security. is it really that hard to add the term "malware" to his search query? could he not find a few and then use them as a seed in an algorithm that crawls backwards and forwards through scientific papers by citation? did he even bother to look at Virus Bulletin? does he even know what that is?

security isn't the only thing that is incredibly broad - so too is the practice and discipline of science itself. there are many different fields and each one does things in their own particular way. we do not perform randomized controlled trials on the cosmos. as a general rule we do not intervene in volcano formation. the work being done at the large hadron collider does not follow exactly the same methodologies that are used in medical science. are we to judge cosmology, volcanology, or particle physics poorly because of this? no of course not. a question you might well ask is what kind of science should logically be used when it comes to studying computer security and, while i suspect multiple scientific disciplines could be useful, the one that springs immediately to mind is computer science. does computer science look anything like medical science? as someone with a degree in computer science i can tell you the answer is emphatically no. we do many things in computer science but randomized controlled trials are not among them (because computers are not people). while Hanno may style himself as "scientifically minded" he doesn't seem to demonstrate an appreciation for the breadth of valid scientific research methodologies and one is left to wonder if he's familiar with any kind of science outside of medicine.

when it comes right down to it, it's this apparent lack of familiarity with the subject matter he's talking about that i found most troubling about Hanno's talk.what is anti-virus software really? what is av testing methodology really? what does science really look like? where do you look for scientific research into malware and anti-malware? these all seem to be questions Hanno struggles with, which brings us back to the subject of why he likes to avoid the term "security researcher". if i had to venture a guess i'd say it's because he doesn't do research, even the basic research necessary to understand the subject matter. as such i would say avoiding the term "security researcher" is probably appropriate (for now).

i'm not sure what one can say in a talk about a subject one hasn't done one's homework on, but hopefully that can improve in the future. Hanno referenced Tavis Ormandy during his talk (as people who criticize AV like to do). Tavis' work on AV also suffered from a lack of understanding in the beginning, but he improved over time and, while he still has room for more improvement, now has arguably done some good work in finding vulnerabilities in AV and holding vendor's accountable for the quality of their software. i'm certain Hanno can also improve. i know there are real criticisms to be made of AV software and the industry behind it, but they have to be informed, they have to come from a place of real knowledge and understanding. i look forward to Hanno reaching that place.

Friday, October 21, 2016

highlights from #sector2016

i haven't posted about the sector conference in a number of years, in spite of attending. let's break that trend. here's some highlights from this year's conference.

  • edward snowden - he was surprisingly well prepared to talk about canadian policy and events
  • marketing gimmicks - hockey pucks are one thing, but give me a key and tell me that there's a lock that it might fit and you're darn right i'm going to go find out if it fits. i gather there was a prize i could have won if it did fit but i didn't pay much attention to that. a friend at work said he'd have bought their product on the strength of that gag alone.
  • ransomware - ransomware seemed to be the theme this year. i lost track of how many talks were about or mentioned ransomware. 2016 really does seem like the year of ransomware. i caught the tail end of talk from someone at sophos where they described a feature for rolling back encrypted files using a proprietary backup mechanism. if other vendors aren't doing something like this you're leaving money on the table. (that's right, i know how you vendors think)
  • mikko hypponen - great perspective on what protecting computers has evolved into: protecting society because it now runs on computers
  • the security problems of an 11 year old and how to solve them - this talk was given by an actual 11 year old who could probably put some professionals to shame. this is the talk i most look forward to sharing with people at work when the videos become available.
  • mikko's "virus" floppy disk that he left behind - this isn't a highlight because someone from the AV industry was careless with infectious materials but rather because when it was found people wanted to find a computer they could stick it into and see what was there. you'd think the difficulty in finding the hardware necessary to read a 5 1/4" floppy would make such a disk a relatively safe prop to use, even if there was a virus on it. leave it to infosec pros to try and find ways around such barriers. now you know where shadow IT comes from, folks. by the way, don't tell mikko.
there were other good talks and keynotes, of course, but i'm not going to detail every talk i attended and every person i met. these are the things that really stood out to me and if you want to know more you should have gone yourself.

Friday, September 02, 2016

the anti-virus harm balance

anti-virus software, like all software, has defects. sometimes those defects are functional and manifest in a failure to do something the software was supposed to do. some other times the defects manifest in the software doing something it was never supposed to do, which can have security implications so we classify them as software vulnerabilities. over the years the software vulnerabilities in anti-virus software has been gaining an increasing amount of attention by the security community and industry - so much so that these days there are people in those groups expressing the opinion that, due to the presence of those vulnerabilities, anti-virus software does more harm than good.

the reasoning behind that opinion goes something like this: if anti-virus software has vulnerabilities then it can be attacked, so having anti-virus software installed increases the attack surface of the system and makes it more vulnerable. worse still, anti-virus software is everywhere, in part because of well funded marketing campaigns but also because in some situations it's mandated by law. add to that the old but still very popular opinion that anti-virus software isn't effective anymore and it starts looking like a perfect storm of badness waiting to rain on everyone's parade.

there's a certain delicious irony in the idea that software intended to close avenues of attack actually opens them instead, but as appealing as that irony is, is it really true? certainly each vulnerability does open an avenue of attack, but is it really doing that instead of closing them or is it as well as closing them?

if an anti-virus program stops a particular piece of malware, it's hard to argue that it hasn't closed the avenue of attack that piece of malware represented. it's also hard to argue that anti-virus software doesn't stop any malware - i don't think anyone in the anti-AV camp would try to argue that because it's so demonstrably false (anyone with a malware collection can demonstrate anti-virus software stopping at least one piece of malware). indeed, the people who criticize anti-virus software usually complain not about set of malware stopped by AV being too small but rather that the set of malware stopped by AV doesn't include the malware that matters most (the new stuff).

so, since anti-virus does in fact close avenues of attack, that irony about opening avenues of attack instead of closing them isn't strictly true. but what about the idea that anti-virus software does more harm than good? well, for that to be true anti-virus software would have to open more avenues of attack than it closes. i don't know how many vulnerabilities any given anti-virus product has so i can't give an exact figure of how many avenues of attack are opened. i doubt anyone else can do so either (though i imagine there are some who could give statistical estimates based on the size of the code base). the other side of the coin, however, is one we have much better figures for. the number pieces of malware that better known anti-virus programs stop (and therefore the number of avenues of attack closed) is in the millions if not tens of millions and that number increases by thousands each day. can the number of vulnerabilities in anti-virus software really compare with that?

it's said that windows has 50 million lines of code. if an anti-virus product were comparable (i suspect in reality it would have fewer lines of code) and if that anti-virus product only stops 5 million pieces of malware (i suspect the real number would be higher) then in order for that anti-virus product to do more harm than good it would need to have at least one vulnerability for every 10 lines of code. that would be ridiculously bad software considering such metrics are usually estimated per 1000 lines of code.

now one might argue (in fact i'm sure many will) that those millions of pieces of malware that anti-virus software stops don't really represent actual avenues of attack because for the most part they aren't actually being used anymore. they've been abandoned. counting them as closed avenues of attack isn't realistic. the counter-argument to that, however, is to examine why they were abandoned in the first place. the reason is obvious, they were abandoned because anti-virus software was updated to stop them. the only reason why malware writers continue making new malware instead of resting on their laurels and using existing malware in perpetuity is because once anti-virus software can detect that existing malware it generally stops being a viable avenue of attack. so rather than the abandonment of that malware counting against anti-virus software's record of closing avenues of attack it's actually closer to being AV's figurative body count.

there is still malware out there that anti-virus software hasn't yet stopped, and as that set is continually replenished it's unlikely that anti-virus software will stop all the malware. it has stopped an awful lot so far, however, so the next time someone says anti-virus software does more harm than good (due to it's vulnerabilities) ask them for their figures on the number of vulnerabilities in anti-virus products and see how it compares with the number of things anti-virus software stops. i have a feeling you'll find those people are full of it.

Tuesday, September 01, 2015

there's a quality problem in the anti-malware industry

if you follow infosec news sources at all, by now you've probably heard about the claim made by an anonymous pair of ex-kaspersky employees that kaspersky labs weaponized false positives.

more specifically, the claim is that engineers at kaspersky labs were directed to reverse engineer competing products and use that knowledge to alter legitimate system files by inserting malicious looking code into them so that they would both seem like files that should be detected and be similar enough to the original file that the competing product will also act on the legitimate file and in so doing cause problems for users of those competing products.

i've heard this described as fake malware, but for the life of me i can't see why it should be called fake. the altered files may not do anything malicious when executed, but they're clearly designed to exploit those competing products. furthermore, there is clearly a damaging payload. this isn't fake malware, it's real malware. it may launch it's malicious payload in an unorthodox and admittedly indirect manner, but this is essentially an exploit.

some consider the detection of these altered files to be false positives because the files don't actually do anything themselves, but since they have malicious intent and indirectly harmful consequences, i think the only real false positives in play here are the original system files that are being mistaken for these modified files.

by all accounts, this type of attack on anti-malware products actually happened. what's new here is the claim that kaspersky labs was responsible at the direction of eugene kaspersky himself. there's a lot of room for doubt. the only data we have to go by so far, besides the historical fact of the attack's existence, is the word of anonymous sources (who potentially have an ax to grind) and some emails that, quite frankly, are easily forged. circumstantially there's also an experiment kaspersky participated in around the same time frame that has similar earmarks to what is being claimed except for the part about tricking competing products into detecting legitimate files as malware.

i don't expect we'll ever know for sure if kaspersky was behind the attacks. doubts have been expressed by members of the industry, but frankly i've seen too many things whitewashed or completely ignored (like partnerships with government malware writers) to take their publicly expressed statements at face value. there are certainly vendors i'd have a harder time believing capable of this but there just doesn't seem to be sufficient evidence that the claims are true. the problem is that i can't imagine any kind of evidence the anonymous sources are likely to have that isn't easy to repudiate. had they taken a stand at the time (like someone with actual scruples would have done) they would have been able to put their names behind their claims - they may have lost their jobs but they surely would have been able to find employment with a different vendor because hiring a whistle-blower would have been good PR.

however, as it stands now, the anonymous sources have to remain anonymous. if they're telling the truth then they are complicit in kaspersky's wrong-doing, and if they're lying they are throwing the entire industry under the bus for no good reason (because this claim fans the fires of that old conspiracy theory about AV vendors being the ones who write the viruses). Either way, to have this claim linked to their real identities now would make them radioactive in the industry. no one would touch them, and for good reason.

long ago it used to be that the industry only employed the highest calibre of researchers. people who were beyond reproach. naturally, in order to grow, the industry has had to hire ever increasing numbers of people and old safeguards against undesirable individuals joining the ranks don't scale very well. increasingly people who aren't beyond reproach are being found amongst the industry's ranks and there appears to be no scenario where these two anonymous sources don't fall into that category. the inclusivity that the general security community embraces (and that the anti-malware industry is increasingly mimicking) has the consequence that blackhats are included. the anti-malware industry is going to have to either figure out if they're ok with that or figure out a way to avoid what the general security community could not.

Tuesday, December 16, 2014

no malware defeats 90% of defenses

yesterday, 'security expert' robert graham penned a blog post claiming that all malware defeats 90% of defenses - a claim made in answer to the FBI's claim that the attack on sony would have been just as successful against 90% of other companies. as you might well imagine, however, robert graham was in error.

the error isn't a straight-forward one, but it is one that most of the security industry makes. it's an error in framing.

the security industry likes to frame the problem as automaton vs. automaton because that facilitates the comforting lie they tell their customers. businesses see security (not incorrectly) as something that costs them time and money and so they search for ways to cut those costs. the security industry, flush with skillful sales people, tells businesses what they want to hear: that they can cut costs and automate much of security, leaving only a handful of personnel left to operate a little like janitorial staff - cleaning up messes and keeping the automaton running smoothly. likewise, the security industry tells consumers what they want to hear as well: that they just need to install a product and that product will take care of security for them automatically.

in security, however, your adversary isn't a thing, it's a person. malware doesn't defeat defenses anymore than a pick and tension wrench defeats the tumblers in a lock. malware is an object, not a subject. it may have some small measure of autonomy (some more so than others), but it doesn't defeat anything - it's not the agent in that kind of scenario, it's simply a proxy for an intelligent adversary.

intelligent adversaries are notoriously good at outsmarting automatons. robert graham provided a wonderful example of that in his own post when he described creating brand new malware that went undetected by the anti-malware software being run by his targets. what he failed to do was take appropriate credit. it wasn't the malware the defeated those defenses, it was a person or persons with APT level skill (even if it didn't require quite that much skill to pull it off - he described it as easy, but easy is a relative term). the targets were compromised, not because they were using substandard defensive technology per se, but because they were relying on automatons to protect them against people.

in a battle of wits between an automaton and an intelligent adversary, the intelligent adversary has the advantage by definition.

so long as the security industry continues to tell their customers what they want to hear instead of what they need to know, those customers are going to continue relying on a stupid box to fend off smart people. that is a recipe for failure no matter what technology is involved.

Monday, November 24, 2014

stealing master passwords is just not that big a deal

by now a lot of people have heard the news that a new version of the citadel trojan steals the master password for password management software. a LOT of electrons have gone into reporting this new development over and over and over again, but it really doesn't seem like it's a big enough deal to warrant all this attention.

while it may be novel to use keylogging to steal specific passwords for password management software, password stealers and keyloggers are anything but new, and the biggest difference between having this new version of citadel on your system or a traditional keylogger is basically that citadel will be able to collect (and therefore compromise) all your passwords faster than a normal keylogger (all at once vs. piecemeal).

that's really all there is to it. from the perspective of a potential victim, citadel isn't doing anything really new, it's just doing it more efficiently. password stealing malware has been out there for a long time and password managers were never meant to combat that particular threat to password security. password managers are meant to facilitate the use of strong, unique passwords which in turn serves to mitigate the risk of compromises to remote systems - compromising the local system is an entirely different problem.

at the end of the day, you can't operate securely with a compromised computer. even if you were to use 2 factor authentication (which could conceivably render password stealing moot) everything else you enter or access would be exposed to potential theft or manipulation if you're using a compromised computer.

i realize it may seem awkward that a class of software security pros have been promoting for years in order to improve security is now being targeted by malware, but it's only awkward because such a needlessly big deal is being made out of it. password management software still mitigates the same risks associated with remote compromises that it always did,  and you're as hosed as you ever were in the event of a local compromise. nothing has actually changed for the people trying to keep their things secure so stop acting like this development changes anything - it doesn't.

Wednesday, September 17, 2014

the PayPal pot calling the Apple Pay kettle black

so if you haven't heard yet, PayPal took out a full page ad in the New York Times trying to drag Apple Pay's name through the mud based on Apple's unfortunate celebrity nude selfie leak. This despite the fact that PayPal happily hands out your email address to anyone you have a transaction with. In essence, PayPal has been leaking email addresses for years and not doing anything about it, so they shouldn't get to criticize others for leaking personal information.

what's the big deal about email addresses? while it's true that we often have to give every site we do a transaction on an email address, we don't have to give them all the same address. in fact, giving each site a different email address happens to be a pretty good way to avoid spam, but more importantly it's a good way to avoid phishing emails, and that's important where PayPal is concerned because PayPal one of the most phished brands in existence.

unfortunately, because PayPal wants all parties in a transaction to be able to communicate with each other, they do the laziest, most brain-dead thing one can imagine to accomplish this: they hand out your PayPal email address to others, which is pretty much the worst email address to do that with. i have actually had to change the disposable email address i use with PayPal because they are apparently incapable of keeping that address out of the hands of spammers, phishers, and other email-based miscreants. furthermore, i also use their service less because i don't want to have to clean up after their mess.

at some point i may have to start creating disposable PayPal accounts and use prepaid debt cards with them. certainly if i were trying to hide from massive spy agencies then that would be the way to go, but if i'm only concerned with mitigating email-borne threats i really shouldn't have to go to that much trouble. there are other, more intelligent things that PayPal could, even should be doing.

  • they could share the email address of your choosing, rather than the one you registered with their service unconditionally. that way you could provide the same address you probably already provided that other party when you created an account on their site. it shouldn't be too difficult for them to verify that address before sharing it with the other party since they already verify the one you register with.
  • they could offer their own private messaging service so that communication could be done through their servers (which would no doubt aid in conflict resolution).
  • they could provide a disposable email forwarding service such that the party you're interacting with gets a unique {something}@paypalmail.com address that forwards the mail on to the email address you registered on PayPal with, and once the transaction is completed to everyone's satisfaction the address is deactivated.
they don't do anything like that, however. here's what you can do right now with the facilities PayPal makes available. it's a more painful and less intuitive process than anything proposed above, but it does work.
  1. before you choose to pay for something with PayPal, log into PayPal and add an email address (the one you want shared with the party you're doing a transaction with) to your profile. PayPal limits you to 8 addresses.
  2. confirm the address by opening the confirmation link that was sent to that address
  3. make that address the primary email address for your account
  4. confirm the change in primary email address (if you have a card associated with your PayPal account, PayPal may ask you to enter the full card number)
  5. at this point you can use PayPal to pay for something and the email address that will be shared with the other party is the one you just added to your PayPal account
  6. once you've paid with PayPal you will probably want to log back into PayPal, change the primary email address back to what it originally was (and confirm the change once again) and then remove the address you added for the purposes of your purchase. the reason you'll likely want to do this is because PayPal sends emails to every address it has on record for you, and those duplicate emails will get old fast.
most people aren't even going to be aware that they can do this to keep their real PayPal email address a secret from 3rd parties. as a result all manner of email-borne threats can and eventually will wind up in what would otherwise have been a trusted email inbox. make no mistake, this isn't PayPal providing a way to keep that email address private, this is a way of manipulating PayPal's features to achieve that effect. there are too many unnecessary steps involved for this to be the intended use scenario.

as such, PayPal is leaking a valuable email address by default every time you pay for something. yes Apple's selfie SNAFU was embarrassing to people, and yes if Apple doesn't do something about that now that they're becoming a payment platform it could be not just embarrassing but financially costly for victims, but PayPal is already assisting in similarly costly outcomes right now (not to mention potential malware outcomes) so they really have no right to be criticizing Apple. Apple, at least, is taking steps to correct their problems - what is PayPal doing?