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OpenDNS To Block and Monitor Conficker Worm

Linker3000 writes "According to The Register, OpenDNS plans to introduce an new service that will prevent PCs infected with the Conficker (aka Downadup) malware from contacting its control servers, and will also make it easy for admins to know if even a single machine under their control has been infected by Conficker: 'Starting Monday, any networks with PCs that try to connect to the Conficker addresses will be flagged on an admin's private statistics page. The service is available for free to both businesses and home users.' With the amount of trouble this worm has caused, perhaps this is a good time to take a look at OpenDNS if you haven't done so already."

14 of 175 comments (clear)

  1. OpenDNS by Anonymous Coward · · Score: 5, Informative

    OpenDNS redirects www.google.com to OpenDNS servers.

    1. Re:OpenDNS by ratbag · · Score: 4, Informative

      http://blog.opendns.com/2007/05/22/google-turns-the-page/

      Don't know if it's a good enough justification by itself, but at least it's a logical explanation.

    2. Re:OpenDNS by fprintf · · Score: 3, Informative

      By default, yes it does. Since your post is right on top at the moment, I'll post something I shared earlier: Here is OpenDNS response to the privacy concerns: http://www.opendns.com/support/article/244

      You can easily turn off the proxy by changing your settings, under the Advanced section at the bottom.

      --
      This post brought to you by your friendly neighborhood MBA.
  2. Re:Do not use OpenDNS by Anonymous Coward · · Score: 5, Informative

    They make money by monitoring your habits. Can any one tell me how they pay their CDN and caching servers bills for millions and millions queries everyday? They sale your private info.

    OpenDNS redirects all your Google search queries though their servers.

    They redirect web browser users or scripts accessing nonexistent domains to a page containing sponsored search results, ads, and a search form. The DNS protocol requires that a query for a nonexistent domain must return the "NXDOMAIN" error response.

  3. Re:Do not use OpenDNS by fprintf · · Score: 5, Informative

    You can turn this feature off. http://www.opendns.com/support/article/244 is their response to questions about privacy.

    For those that have OpenDNS running, you go to Settings, Advanced and then at the bottom there is the Network Shortcuts section. Uncheck the box "Enable OpenDNS Proxy".

    I have the service and I am quite happy to trade a little privacy for the content filtering done by someone else, without requiring any software installs or any maintenance of IPTables or anything else on my part. It is passive safety, I know, but gives some peace of mind with a teenager who knows his way around computers. It blocks proxies too. If there is an alternative, I'd love to read about it.

    --
    This post brought to you by your friendly neighborhood MBA.
  4. Re:I just found out about this. by slug359 · · Score: 3, Informative

    Not really, no.

    For the NTP pool you send and recieve time data; funnily enough the time is public information.

    Switching your DNS servers to OpenDNS means you end up sending them every domain you visit, and apparently every Google search too.
    Most people would probably want their search terms and domains they visit to stay private, so your analogy between the NTP pool and commercial DNS providers breaks down here.

    (note: I'm not implying sending your DNS data to OpenDNS means it's made public!)

  5. Re:I just found out about this. by Antique+Geekmeister · · Score: 3, Informative

    Use 127.0.0.3, and put that in your /etc/hosts as 'dns.localdomain'. This still reaches your loopback address, but avoids some of the potential reverse DNS confusions with 'localhost.localdomain'.

  6. Re:Maybe I'm off base here but by causality · · Score: 4, Informative

    FTFA:

    .....instructs its drone machines to report to 250 different internet addresses each day. Without the service, admins would have to manually block 1,750 domains each week, or 91,250 each year.

    Wouldn't blocking "this weeks" known IP addresses stop the addition of new ones, rendering the infection impotent?

    That would address a symptom and would do nothing about the actual problem. We keep doing that because we don't want to admit that addressing only symptoms is a failed idea; trying harder and harder to find new ways to implement this idea won't change the fact that it's a failed idea.

    The root problem is the vulnerability of Windows to these types of worms. Yes I am selectively speaking about Microsoft Windows; if I ever start seeing widespread (keyword) worms in the wild (keyword) for *nix operating systems then on that day I'll include them too. Anti-virus seeks to remove or contain an external object to which Windows is vulnerable, so it too addresses only the symptom and not the vulnerability. The reason why *nix operating systems don't generally need anti-virus (unless of course you ask an anti-virus vendor) is because they have a security model that is able to prevent infections from occurring in the first place. This is much simpler and more practical (but creates fewer cottage industries) than sophisticated scanners and high-maintainence databases of tens of thousands of signatures that must be applied to every file or every file operation. It's a lot simpler than pretending that DNS is the correct tool for host security as well.

    If OpenDNS maintains a highly effective, well-maintained blocklist and if many people start using it, what happens next is rather predictable. A worm/virus that can compromise the machine can also alter that machine's DNS settings. It could make the machine stop using OpenDNS or worse (as another poster has pointed out) it could make it use a hostile DNS server. You can expect this to be a standard malware feature if OpenDNS's efforts are successful. That's the downside of participating in an arms race. The best way to avoid an arms race is to realize that mitigation techniques, while not completely useless, have extremely limited utility and that prevention is the only actual cure.

    --
    It is a miracle that curiosity survives formal education. - Einstein
  7. Re:Aren't ISP's, Etc., Selling Data, Too? by Antique+Geekmeister · · Score: 5, Informative

    It could be worse. Does anyone else here remember the 'Site Finder' chaos, when Verisign returned their own sales website domain for all nonexistent .com addresses? As the managers of .com, their behavior screwed up network monitoring tools worldwide, and misdirected huge amounts of misaddressed email to their servers, without warning. Patches were quickly released for every major DNS software package to block it, which is probably the real reason it got dropped: having every DNS server in the world used to the idea that 'I can block the behavior of idiots' is very, very bad for companies like Verisign that have repeatedly misused their position of trust against third parties.

  8. Re:Do not use OpenDNS by Dreadneck · · Score: 3, Informative

    They make money by monitoring your habits. Can any one tell me how they pay their CDN and caching servers bills for millions and millions queries everyday?

    From the site:

    "OpenDNS partners with hardware and service providers to deliver our award-winning security, infrastructure and navigation services."

    They sale your private info.

    There's nothing private about my public IP address. If they can manage to glean personal info from my IP address then, damn, they're good.

    OpenDNS redirects all your Google search queries though their servers.

    From the site:

    "Is OpenDNS running a proxy?

    Yes. Some software, including your (and our) beloved Google Toolbar, intercepts requests made via the address bar so that DNS requests never occur. This creates some usability issues, including making shortcuts - which require DNS requests to be made from the address bar - unreliable. We've designed a simple proxy that ensures the best of Google and OpenDNS work without causing problems.

    When enabled, we route certain requests to a simple proxy which checks for the origin of the request. Shortcut-related traffic gets handled (and redirected) while all other traffic goes to the intended destination untouched. We are not storing or mining any of the data that passes through the proxy. The proxy does nothing malicious - it's designed to make your shortcuts work seamlessly with the Google Toolbar and similar services, giving you the best of both worlds.

    Like all OpenDNS services, the proxy is respectful of your privacy. We do not track any of the searches made through the proxy. In fact, since so many people use Google we automatically rotate and delete the logs frequently. We do not store any of those logs, nor do we perform any non-operational-related analysis of the traffic sent through the proxy at any time. Protecting your privacy and delivering a fantastic navigational experience will always be two of our main goals at OpenDNS. We believe that this solution provides just that, and continues our tradition of innovative services that make your Internet experience with OpenDNS faster, safer and more reliable.

    Ultimately, this proxy serves to enhance the OpenDNS experience and we recommend you leave it enabled.

    They redirect web browser users or scripts accessing nonexistent domains to a page containing sponsored search results, ads, and a search form. The DNS protocol requires that a query for a nonexistent domain must return the "NXDOMAIN" error response.

    You mean if I try to navigate to a nonexistent domain that OpenDNS will A) Inform me of my error B) Present me with a search form and C) Display a few innocuous text ads on the page?

    I'm crushed. Damn, how could they?

    How is that any worse than Google displaying text ads on their search results page? How hard can it be to block those text ads if they really get your panties in that big of a twist? If it bothers you that much, it's not like anyone is holding a gun to your head and forcing you to use their service.

    --
    Power does not corrupt - power attracts the corrupt.
  9. Re:Do not use OpenDNS by Kent+Recal · · Score: 4, Informative

    and add extra features to decades old service without breaking standards.

    But they are breaking the standard. In particular rfc2308,

    under 8:

    Negative caching in resolvers is no-longer optional, if a resolver
          caches anything it must also cache negative answers.

          The SOA record from the authority section MUST be cached. Name error
          indications must be cached against the tuple .
          No data indications must be cached against tuple.

    Note the absence of statements like "lookup failures should silently map to A records that point to webservers serving spam".

  10. Re:I Don't See A Scam by cronot · · Score: 3, Informative

    Well, I can't vouch for the GP, but my ISP has a very flaky DNS service. For some reason, every 3 out of 10 queries for a given DNS returns a NX - or (in layman's terms), every 3 (at least) out 10 times I try to access a website (that is, one specific website, 10 times), Firefox says the domain doesn't exist. After the first 3 errors the domain is found and cached, and all is well, but this annoyed me to no end.

    There were some days when it was bad, and others days the problem never showed up. After trying to diagnose the problem on my end, I finally concluded the problem were my ISP's servers, so I gave up and switched to OpenDNS. Never had the problem again.

  11. Re:Do not use OpenDNS by davidu · · Score: 5, Informative

    I'm the founder of OpenDNS. I've decided to reply even though these comments are heinously wrong, and probably just me feeding the trolls...

    We have never sold user data, ever. We also have no CDN bills, we don't even use a CDN. We've built a global BGP-speaking network with hundreds of peers around the world. I know, because I built it. We peer at LoNAP, LINX, PAIX, SeattleIX and on a few of the Equinix peering fabrics around the US.

    The idea that we would build our business based on monitoring user data is preposterous. I wouldn't stand for it, nor would our employees. I'm confident that all our engineers are just as vocal or more vocal about doing the right thing than you are. We make it very clear how we make money, and it's all over our website. Go to http://guide.opendns.com and do a search. The sponsored results are ads where we get paid, the organic results are regular search results. That's how we make money. We might offer an enterprise for-pay service down the road as some of our customers begin to demand tighter integration with their network but for now, we're happy with our business. And I'm happy to report that we're profitable and stable, even in this economy.

    And as to the OpenDNS proxy. It's true, we do redirect certain Google requests through a proxy so that we can make our OpenDNS shortcuts and some other features work more reliably. Two important things here: First, we peer with Google at every datacenter, so we aren't adding to your latency or anything else. Second, we don't log and store any data and we certainly don't care about it. We prefer to be able to confidently say we aren't keeping data on it. Of course, you are welcome to disable it by going into your settings and disabling the OpenDNS proxy. That's it. Do that and we don't ever see the request. Pretty easy. End of story.

    David Ulevitch
    Founder, OpenDNS

    --

    # Hack the planet, it's important.
  12. Re:Do not use OpenDNS by ConceptJunkie · · Score: 3, Informative

    This guy has a 2-digit UID, how could he possibly not be on the level? ;-)

    Seriously, I've been using OpenDNS for a year or so, and based on what I know and everything I've read here minus David Ulevitch's description I don't really see a problem, just a lot of people overreacting. After reading what he had to say, I am confident that my gut feeling was accurate... unless of course he's lying, which I have no reason to believe.

    --
    You are in a maze of twisty little passages, all alike.