Slashdot Mirror


Paul Vixie Responds To DNS Hole Skeptics

syncro writes "The recent massive, multi-vendor DNS patch advisory related to DNS cache poisoning vulnerability, discovered by Dan Kaminsky, has made headline news. However, the secretive preparation prior to the July 8th announcement and hype around a promised full disclosure of the flaw by Dan on August 7 at the Black Hat conference has generated a fair amount of backlash and skepticism among hackers and the security research community. In a post on CircleID, Paul Vixie offers his usual straightforward response to these allegations. The conclusion: 'Please do the following. First, take the advisory seriously — we're not just a bunch of n00b alarmists, if we tell you your DNS house is on fire, and we hand you a fire hose, take it. Second, take Secure DNS seriously, even though there are intractable problems in its business and governance model — deploy it locally and push on your vendors for the tools and services you need. Third, stop complaining, we've all got a lot of work to do by August 7 and it's a little silly to spend any time arguing when we need to be patching.'"

20 of 147 comments (clear)

  1. I'm not worried by niceone · · Score: 5, Funny

    I just remember the IP addresses and type them in myself. How hard is that?

    1. Re:I'm not worried by socsoc · · Score: 4, Interesting

      That's really hard on web servers that host multiple domains on a single IP. Virtual hosting isn't exactly a new idea.

    2. Re:I'm not worried by Klaus_1250 · · Score: 5, Funny

      Why is that hard? Still works with IP-addresses. The only thing you need to do is to supply the Host-field as per HTTP/1.1.

      --
      It only takes one man to change the Wisdom of the Crowd to Tyranny of the Masses.
    3. Re:I'm not worried by cnettel · · Score: 4, Funny

      I just remember the IP addresses and type them in myself. How hard is that?

      That's all well and dandy until banner ads start flashing subliminal messages of unauthorized zone updates to you.

    4. Re:I'm not worried by Toutatis · · Score: 4, Funny

      How can you know then that the flaw isn't in your mind too.

    5. Re:I'm not worried by Nullav · · Score: 5, Funny

      Hey!
      I am an unpatched DNS server, you insensitive clod!

      --
      I just read Slashdot for the articles.
    6. Re:I'm not worried by Lennie · · Score: 4, Funny

      That's why 'smart' people use /etc/hosts. That solves the problem of remembering and of the HTTP-host-header.

      --
      New things are always on the horizon
  2. The back-biting is shameful by hal9000(jr) · · Score: 5, Insightful

    this article at information week said it best the day after the announcement.

    Geez, if you want responsible disclosure, you have to trust the experts when they say "it's new and it's bad"

    1. Re:The back-biting is shameful by wild_quinine · · Score: 4, Funny

      If there's one thing that everyone should have learned by now, if someone says "trust me", you should be skeptical.

      No, you're off message. They need to click continue, because the screen has gone all dark and they can't get back to their web browser.

    2. Re:The back-biting is shameful by tyler.willard · · Score: 4, Interesting

      This issue may be huge. But without all the necessary information, you can't make an informed decision as to whether or not you believe it is.

      That same information that allows you to make an "informed decision", as you so blithely put it, puts the integrity of the entire infrastructure and, more to the point, the information security of a whole lof of people at tremendous risk. Dammit, that's the whole point of the OP's observation and why people argue about disclosure in the first place.

    3. Re:The back-biting is shameful by Goaway · · Score: 4, Insightful

      So, you figure eighty vendors coordinated a simultaneous patch for some issue that is not really a big deal, probably just some guys vying for attention?

    4. Re:The back-biting is shameful by tyler.willard · · Score: 4, Insightful

      Maybe then we wouldn't have software vendors taking weeks, months or years to patch remotely exploitable bugs (yes, I'm looking at YOU, Microsoft)

      Sure you would; and the blame for any damage would be blamed on who made the disclosure.

      There is nothing wrong with how this was/is being handled. Limited disclosure with a solid and "reasonable" deadline is a perfectly fine way to balance the myriad issues with security threats.

  3. Doctors make the worst patients by wild_quinine · · Score: 5, Insightful
    ... and IT admins make the worst end users.

    Knowing how to run a system is not purely technical knowledge, it's also a measure of professional ability. That means knowing when to take advice, and knowing who to take it from.

  4. Re:What is Secure DNS by Anonymous Coward · · Score: 5, Informative

    "The Domain Name System Security Extensions (DNSSEC) are a suite of IETF specifications for securing certain kinds of information provided by the Domain Name System (DNS) as used on Internet Protocol (IP) networks. It is a set of extensions to DNS which provide to DNS clients (resolvers):

            * Origin authentication of DNS data.
            * Data integrity.
            * Authenticated denial of existence."

    http://en.wikipedia.org/wiki/DNSSEC

  5. Re:Unfortunately, what else is new? by danFL-NERaves · · Score: 5, Funny

    Your mad ad hominem attack skills have convinced everyone that Paul Vixie is the know nothing douchebag in this conversation. Kudos!

  6. Re:Unfortunately, what else is new? by gregmark · · Score: 4, Informative

    Randomizing UDP source ports does not solve the problem, it only makes it more difficult to impersonate the responding DNS server. Secure DNS makes this kind of impersonation impossible, or at least allows us to bask in the warm glow of impossible.

    The DJB vs BIND thing is an illusion. Whatever everyone agrees is the best implementation should win and I doubt that Paul Vixie or anyone else at ISC thinks differently.

    But it has become abundantly clear to me that DJB and his minions (of which I assume you are one) have failed to matter in most ways, not because of your ideas, but because of the brusque, immature manner in which those ideas are submitted for consideration, outside the standards committees which have served the Internet well for 30 years.

  7. So its not the same flaw? by BOFslime · · Score: 4, Informative

    I'm having trouble with Paul Vixies' line:

    Q: "This is the same attack as described way back in ."
    A: No, it's not.

    When Dan Kaminsky states in his blog.

    "DJB was right. All those years ago, Dan J. Bernstein was right: Source Port Randomization should be standard on every name server in production use."
    and
    " 1) It's a bug in many platforms 2) It's the exact same bug in many platforms (design bugs, they are a pain) " How is this not the same flaw DJB described?

    1. Re:So its not the same flaw? by hal9000(jr) · · Score: 4, Informative

      1) It's a bug in many platforms 2) It's the exact same bug in many platforms (design bugs, they are a pain) " How is this not the same flaw DJB described?

      You are looking at two separate issues. The flaw Kaminsky found is apparently a newly discovered design flaw that makes DNS forging easy even with todays, unpatched DNS servers. In the advisory, they discussed previous problems with generating the transactionID to explain the problem and point out that what Dan found is not something already known (alot of people missed that very obvious point).

      The second seperate, issue is UDP source port randomization. That is what Kaminsky was referring to DJB's solution. Kaminsky's assertion is that UDP source port is a good development practice which DJB incorporated into his DNS server.

      Bear in mind that UDP source port generation doesn't solve the underlying problem, it simply makes blind DNS forging more difficult because now an attacker has to guess both a pseudo random transaction ID and a pseudo random UDP source port number. Alot of DNS servers and OS, simply picked source port numbers incrementally or in the case of a DNS server, re-used the some one over and over.

      I don't know hom much more difficult DNS forging will be by randomizing the UDP source port numbers. The additional keyspace is (2^16-1023) and you can probably divide that in half again. But it's better then nothing and probably provides enough time (the time it would take an attacker to blindly guess the transactionID and UDP source port number) for the actual response to hit the DNS server. In DNS, the first response wins.

  8. It's all a liberal plot by spun · · Score: 4, Funny

    DNS cache poisoning is a myth cooked up by the liberal media and DNS scientists to implement their anti capitalist agenda.

    And if it isn't a myth, then it certainly isn't man made, it's a natural phenomenon and there's nothing we can do about it.

    --
    - None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
  9. A simple test to run by GeorgeK · · Score: 4, Informative

    In a comment to a question I posted for the CircleID article, Paul Vixie posted a nice and simple test that people can run to see how vulnerable they are:

    dig porttest.dns-oarc.net in txt

    FAIR or GOOD means you're ok, but POOR (which is the result I got) means you should be worried.