Posts in General

Cowed Through DNS

Thursday, March 04, 2010 by Pascal Meunier in General,

May 2010 will mark the 4th aniversary of our collective cowing by spammers, malware authors and botnet operators. In 2006, spammers squashed Blue Frog. They made the vendor of this service, Blue Security, into lepers, as everyone became afraid of being contaminated by association and becoming a casualty of the spamming war. Blue Frog hit spammers were it counted -- in the revenue stream, simply by posting complaints to spamvertized web sites. It was effective enough to warrant retaliation. DNS was battered into making Blue Security unreachable. The then paying commercial clients of Blue Security were targetted, destroying the business model; so Blue Security folded [1]. I was stunned that the "bad guys" won by brute force and terror, and the security community either was powerless or let it go. Blue Security was even blamed for some of their actions and their approach. Blaming the victims for daring to organize and attempt to defend people, err, I mean for provoking the aggressor further, isn't new. An open-source project attempting to revive the Blue Frog technology evaporated within the year. The absence of interest and progress has since been scary (or scared) silence.

According to most sources, 90-95% of our email traffic has been spam for years now. Not content with this, they subject us to blog spam, friendme spam, IM spam, and XSS (cross-site scripting) spam. That spam or browser abuse through XSS convinces more people to visit links and install malware, thus enrolling computers into botnets. Botnets then enforce our submission by defeating Blue Security type efforts, and extort money from web-based businesses. We can then smugly blame "those idiots" who unknowingly handed over the control over their computers, with a slight air of exasperation. It may also be argued that there's more money to be made selling somewhat effective spam-fighting solutions than by emulating a doomed business model. But in reality, we've been cowed.

I had been hoping that the open source project could make it through the lack of a business model; after all, the open source movement seems like a liberating miracle. However, the DNS problem remained. So, even though I didn't use Blue Frog at the time, I have been hoping for almost 4 years now that DNS would be improved to resist the denial of service attacks that took Blue Security offline. I have been hoping that someone else would take up the challenge. However, all we have is modest success at (temporarily?) disabling particular botnets, semi-effective filtering, and mostly ineffective reporting. Since then, spammers have ruled the field practically uncontested.

Did you hear about Comcast's deployment of DNSSEC [2]? It sounds like a worthy improvement; it's DNS with security extensions, or "secure DNS". However, Denial-of-service (DoS) prevention is out-of-scope of DNSSEC! It has no DoS protections, and moreover there are reports of DoS "amplification attacks" exploiting the larger DNSSEC-aware response size [3]. Hum. Integrity is not the only problem with DNS! A search of IEEE Explore and the ACM digital library for "DNS DoS" reveals several relevant papers [4-7], including a DoS-resistant backwards compatible replacement for the current DNS from 2004. Another alternative, DNSCurve has protection for confidentiality, integrity and availability (DoS) [8], has just been deployed by OpenDNS [9] and is being proposed to the IETF DNSEXT working group [10]. This example of leadership suggests possibilities for meaningful challenges to organized internet crime. I will be eagerly watching for signs of progress in this area. We've kept our head low long enough.

References
1. Robert Lemos (2006) Blue Security folds under spammer's wrath. SecurityFocus. Accessed at http://www.securityfocus.com/news/11392
2. Comcast DNSSEC Information Center Accessed at http://www.dnssec.comcast.net/
3. Bernstein DJ (2009) High-speed cryptography, DNSSEC, and DNSCurve. Accessed at: http://cr.yp.to/talks/2009.08.11/slides.pdf
4. Fanglu Guo, Jiawu Chen, Tzi-cker Chiueh (2006) Spoof Detection for Preventing DoS Attacks against DNS Servers. 26th IEEE International Conference on Distributed Computing Systems.
5. Kambourakis G, Moschos T, Geneiatakis D, Gritzalis S (2007) A Fair Solution to DNS Amplification Attacks. Second International Workshop on Digital Forensics and Incident Analysis.
6. Hitesh Ballani, Paul Francis (2008) Mitigating DNS DoS attacks. Proceedings of the 15th ACM conference on Computer and communications security
7. Venugopalan Ramasubramanian, Emin Gün Sirer (2004) The design and implementation of a next generation name service for the internet. Proceedings of the 2004 conference on Applications, technologies, architectures, and protocols for computer communications
8. DNSCurve: Usable security for DNS (2009). Accessed at http://dnscurve.org/
9. Matthew Dempsky (2010) OpenDNS adopts DNSCurve. Accessed at http://blog.opendns.com/2010/02/23/opendns-dnscurve/
10. Matthew Dempsky (2010) [dnsext] DNSCurve Internet-Draft. Accessed at http://www.ops.ietf.org/lists/namedroppers/namedroppers.2010/msg00535.html

Blast from the Past

Thursday, February 25, 2010 by spaf in General, R&D, Secure IT Practices,

Yes, I have been quiet (here) over the last few months, and have a number of things to comment on. This hiatus is partly because of schedule, partly because I had my laptop stolen, and partly health reasons. However, I'm going to try to start back into adding some items here that might be of interest.

To start, here is one item that I found while cleaning out some old disks: a briefing I gave at the NSA Research division in 1994. I then gave it, with minor updates, to the DOD CIO Council (or whatever their name was/is -- the CNSS group?), the Federal Infosec Research Council, and the Criticial Infrastructure Commission in 1998. In it, I spoke to what I saw as the biggest challenges in protecting government systems, and what were major research challenges of the time.

I have no software to read the 1994 version of the talk any more, but the 1998 version was successfully imported into Powerpoint. I cleaned up the fonts and gave it a different background (the old version was fugly) and that prettier version is available for download. (Interesting that back then it was "state of the art" :-)

I won't editorialize on the content slide by slide, other than to note that I could give this same talk today and it would still be current. You will note that many of the research agenda items have been echoed in other reports over the succeeding years. I won't claim credit for that, but there may have been some influences from my work.

Nearly 16 years have passed by, largely wasted, because the attitude within government is still largely one of "with enough funding we can successfully patch the problems." But as I've quoted in other places, insanity is doing the same thing over and over again and expecting different results. So long as we believe that simple incremental changes to the existing infrastructure, and simply adding more funding for individual projects, is going to solve the problems then the problems will not get addressed -- they will get worse. It is insane to think that pouring ever more funding into attempts to "fix" current systems is going to succeed. Some of it may help, and much of it may produce some good research, but overall it will not make our infrastructure as safe as it should be.

Yesterday, Admiral (ret) Mike McConnell, the former Director of National Intelligence in the US, said in a Senate committee hearing that if there were a cyberwar today, the US would lose. That may not be quite the correct way of putting it, but we certainly would not come out of it unharmed and able to claim victory. What's more, any significant attack on the cyberinfrastructure of the US would have global repercussions because of the effects on the world's economy, communications, trade, and technology that are connected by the cyber infrastructure in the US.

As I have noted elsewhere, we need to do things differently. I have prepared and circulated a white paper among a few people in DC about one approach to changing the way we fund some of the research and education in the US in cybersecurity. I have had some of them tell me it is too radical, or too different, or doesn't fit in current funding programs. Exactly! And that is why I think we should try those things -- because doing more of the same in the current funding programs simply is not working.

But 15 years from now, I expect to run across these slides and my white paper, and sadly reflect on over three decades where we did not step up to really deal with the challenges. Of course, by then, there may be no working computers on which to read these!

Drone “Flaw” Known Since 1990s Was a Vulnerability

Friday, December 18, 2009 by Pascal Meunier in General,

"The U.S. government has known about the flaw since the U.S. campaign in Bosnia in the 1990s, current and former officials said. But the Pentagon assumed local adversaries wouldn't know how to exploit it, the officials said." Call it what it is: it's a vulnerability that was misclassified (some might argue that it's an exposure, but there is clearly a violation of implicit confidentiality policies). This fiasco is the result of the thinking that there is no vulnerability if there is no threat agent with the capability to exploit a flaw. I argued against Spaf regarding this thinking previously; it is also widespread in the military and industry. I say that people using this operational definition are taking a huge risk if there's a chance that they misunderstood either the flaw, the capabilities of threat agents, present or future, or if their own software is ever updated. I believe that for software that is this important, an academic definition of vulnerability should be used: if it is possible that a flaw could conceptually be exploited, it's not just a flaw, it's a vulnerability, regardless of the (assumed) capabilities of the current threat agents. I maintain that (assuming he exists for the sake of this analogy) Superman is vulnerable to kryptonite, regardless of an (assumed) absence of kryptonite on earth.

The problem is that it is logically impossible to prove a negative, e.g., that there is no kryptonite (or that there is no God, etc...). Likewise, it is logically impossible to prove that there does not exist a threat agent with the capabilities to exploit a given flaw in your software. The counter-argument is then that the delivery of the software becomes impractical, as the costs and time required escalate to remove risks that are extremely unlikely. However, this argument is mostly security by obscurity: if you know that something might be exploitable, and you don't fix it because you think no adversary will have the capability to exploit it, in reality, you're hoping that they won't find or be told how (for the sake of this argument, I'm ignoring brute force computational capabilities). In addition, exploitability is a thorny problem. It is very difficult to be certain that a flaw in a complex system is not exploitable. Moreover, it may not be exploitable now, but may become so when a software update is performed! I wrote about this in "Classes of vulnerabilities and attacks". In it, I discussed the concept of latent, potential or exploitable vulnerabilities. This is important enough to quote:

"A latent vulnerability consists of vulnerable code that is present in a software unit and would usually result in an exploitable vulnerability if the unit was re-used in another software artifact. However, it is not currently exploitable due to the circumstances of the unit’s use in the software artifact; that is, it is a vulnerability for which there are no known exploit paths. A latent vulnerability can be exposed by adding features or during the maintenance in other units of code, or at any time by the discovery of an exploit path. Coders sometimes attempt to block exploit paths instead of fixing the core vulnerability, and in this manner only downgrade the vulnerability to latent status. This is why the same vulnerability may be found several times in a product or still be present after a patch that supposedly fixed it.

A potential vulnerability is caused by a bad programming practice recognized to lead to the creation of vulnerabilities; however the specifics of its use do not constitute a (full) vulnerability. A potential vulnerability can become exploitable only if changes are made to the unit containing it. It is not affected by changes made in other units of code. For example, a (potential) vulnerability could be contained in the private method of an object. It is not exploitable because all the object’s public methods call it safely. As long as the object’s code is not changed, this vulnerability will remain a potential vulnerability only.

Vendors often claim that vulnerabilities discovered by researchers are not exploitable in normal use. However, they are often proved wrong by proof of concept exploits and automated attack scripts. Exploits can be difficult and expensive to create, even if they are only proof-of-concept exploits. Claiming unexploitability can sometimes be a way for vendors to minimize bad press coverage, delay fixing vulnerabilities and at the same time discredit and discourage vulnerability reports. "

Discounting or underestimating the capabilities, current and future, of threat agents is similar to the claims from vendors that a vulnerability is not really exploitable. We know that this has been proven wrong ad nauseam. Add configuration problems to the use of the "operational definition" of a vulnerability in the military and their contractors, and you get an endemic potential for military catastrophies.

Talking to the Police All the Time

Tuesday, December 08, 2009 by Pascal Meunier in General,

I started writing this entry while thinking about the "if you have nothing to hide, then you have nothing to fear" fallacy. What do you say to someone who says that they have nothing to hide, or that some information about them is worthless anyway, so they don't care about some violation of their privacy? What do you say to a police officer who says that if you have nothing to hide then you have nothing to fear by answering questions? It implies that if you refuse to answer then you're probably "not innocent". That "pleading the 5th" is now used as a joke to admit guilt in light banter, is a sign of how pervasive the fallacy has become. It's followed closely with "where there's smoke there's probably fire" when discussing someone's arrest, trial, or refusal to answer questions. However, in the field of information security, it is an everyday occurrence to encounter people who don't realize the risks to which they are exposed. So why is this fallacy so irritating?

Those kind of statements expose naïveté or, if intended as a manipulative statement, perversity. It takes a long time to explain the risks and convince others that they are real, and that they are really exposed to them, and what the consequences might be. Even if you could somehow manage to explain it convincingly on the spot, before you're done, chances are that you'll be dismissed as a "privacy nut". In addition, you rarely have that kind of time to make a point in a normal discussion. So, that fallacy is often a successful gambit simply because it discourages someone from trying to explain why it's so silly.

You may buy some time by mentioning anecdotes such as the man falsely accused of arson because by coincidence, he bought certain things in a store at a certain time (betrayed by his grocery loyalty card) [1]. Or, there's the Indiana woman who bought for her sick family just a little too much medication containing pseudoephedrine, an ingredient used in the manufacture of crystal meth [2]. Possibilities for the misinterpretation of data or the inappropriate enforcement of bad laws are multiplied by the ways in which it can be obtained. Police can stick a GPS-tracking device on anyone they want without getting a search warrant [3] or routinely use your own phone's GPS [4]. Visiting a web page, regardless of whether you used an automated spider, clicked on a linked manually, perhaps even being tricked into doing it, or were framed by a malicious or compromised web site, can trigger an FBI raid [5] (remember goatse? Except it's worse, with a criminal record for you). There are also the dumb things people post themselves, for example on Facebook, causing them to lose jobs, opportunities for jobs, or even get arrested [6].

Regardless, people always think that happens only to others, that "they were dumb and I'm not" or that they are isolated incidents. This is why I was delighted to find this video of a law professor explaining why talking to police can be a bad idea [7]. Even though I knew that "everything you say can be used against you", I was surprised to learn that nothing you say can be used in your defense. This asymmetry is a rather convincing argument for exercising 5th amendment rights. Then there are the chances that even though you are innocent, due to the stress or excitement you will exaggerate or say something stupid. For example, you might say you've never touched a gun in your life -- except you did once a long time ago when you were a teen maybe, and forgot about it but there's a photo proving that you lied (apparently, that you didn't mean to lie matters little). People say stupid things in less stressful circumstances. Why take the chance? There are also coincidences that look rather damning and bad for you. Police sometimes make mistakes as well. The presentation is well-made and is very convincing; I recommend viewing it.

There are so many ways in which private information can be misinterpreted and used against you or to your disadvantage, and not just by police. Note that I agree that we need an effective police; however, there's a line between that and a surveillance society making you afraid to speak your mind in private, afraid to buy certain things at the grocery store, afraid to go somewhere or visit a web site, or afraid of chatting online with your friends, because you never know who will use anything you say or do against you and put it in the wrong context. In effect, you may be speaking to the police all the time but don't realize it. Even though considering each method separately, it can be argued that technically there isn't a violation of the 5th amendment, the cumulative effect may violate its intent.

Then, after I wrote most of this entry, Google CEO Eric Schmidt declared that "If you have something that you don't want anyone to know, maybe you shouldn't be doing it in the first place" [8]. I'm afraid that's a realistic assessment, even if it's a lawful activity, given the "spying guides" published by the likes of Yahoo!, Verizon, Sprint, Cox, SBC, Cingular, Nextel, GTE, Voicestream for law enforcement, and available at Cryptome [9]. The problem is that you'll then live a sad life devoid of personal liberties. The alternative shrug and ignorance of the risks is bliss, until it happens to you.

[1] Brandon Sprague (2004) Fireman attempted to set fire to house, charges say. Times Snohomish County Bureau, Seattle Times. Accessed at http://seattletimes.nwsource.com/html/localnews/2002055245_arson06m.html

[2] Mark Nestmann (2009) Yes, You ARE a Criminal…You Just Don't Know it Yet. In "Preserving your privacy and more", November 23 2009. Accessed at http://nestmannblog.sovereignsociety.com/2009/11/yes-you-are-a-criminalyou-just-dont-know-it-yet.html

[3] Chris Matyszczyk (2009) Court says police can use GPS to track anyone. Accessed at http://news.cnet.com/8301-17852_3-10237353-71.html

[4] Christopher Soghoian (2009) 8 Million Reasons for Real Surveillance Oversight. Accessed at http://paranoia.dubfire.net/2009/12/8-million-reasons-for-real-surveillance.html

[5] Declan McCullagh (2009) FBI posts fake hyperlinks to snare child porn suspects. Accessed at: http://news.cnet.com/8301-13578_3-9899151-38.html

[6] Mark Nestmann (2009) Stupid Facebook Tricks. In "Preserving your privacy and more", November 27 2009. Accessed at http://nestmannblog.sovereignsociety.com/2009/11/stupid-facebook-tricks.html

[7] James Duane (2008) Don't Talk to Police. http://www.youtube.com/watch?v=i8z7NC5sgik

[8] Ryan Tate (2009) Google CEO: Secrets Are for Filthy People. Accessed at http://gawker.com/5419271/google-ceo-secrets-are-for-filthy-people

[9] Cryptome. Accessed at http://cryptome.org/
Last edited Jan 25, as per emumbert1's suggestion (see comments).

“Verified by VISA”: Still Using SSNs Online, Dropped by PEFCU

Thursday, November 26, 2009 by Pascal Meunier in General,

I have written before about the "Verified by VISA" program. While shopping for Thanksgiving online this year, I noticed that Verified by Visa scripts were blocked by NoScript, and I could complete my purchases without authenticating. It was tempting to conclude that the implementation was faulty, but a few phone calls clarified that the Purdue Employee Federal Credit Union stopped participating in the program. I have ambivalent feelings about this. I'm glad that PEFCU let us escape from the current implementation and surprise enrollment based on SSN at the time of purchase, and SSN-based password reset. Yet, I wish a password-protection system was in place because it could significantly improve security (see below). Getting such a system to work is difficult, because in addition to needing to enroll customers, both banks and merchants have to support it. For the sake of curiosity, I counted the number of participating stores in various countries, as listed on the relevant VISA web sites:

Country	Number of Stores
USA	126
Europe	183
Thailand	439
Taiwan	144
Japan	105
China	90
Singapore	65
Malaysia	27
Hong Kong	20
Vietnam	17
Australia	13
India	7
Others	0

Multiply this by the fraction of participating banks (data not available for the US), and for a program that started in 2001, that's spotty coverage. Adoption would be better by getting people to enroll when applying for credit cards, when making a payment, by mail at any time, or in person at their bank. The more people adopt it, the more stores and banks will be keen on reducing their risk as the cost per participating card holder would decrease. Ambushing people at the time of an online purchase with an SSN request violates the security principle of psychological acceptability. The online password reset based on entering your SSN, which I had criticized, is still exposing people to SSN-guessing risks, and also the only means to change your password. I wish that VISA would overhaul the implementation and use an acceptable process (e.g., a nonce-protected link via email to a page with a security question). The reason I'm interested is because I'd rather have a password-protected credit card, and a single password to manage, than a hundred+ online shopping accounts that keep my credit card information with varying degrees of (in)security. Using an appropriate choke-point would reduce attack surface, memorization requirements, and identity theft.

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