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Re: [opennic-discuss] botnets mitigation


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  • From: Jacob Bachmeyer <jcb62281 AT gmail.com>
  • To: discuss AT lists.opennicproject.org
  • Subject: Re: [opennic-discuss] botnets mitigation
  • Date: Sun, 10 Jun 2018 19:31:30 -0500

This will not solve the problem of criminal botnets using the system. At best, this will force the crooks to start using the OpenNIC DNS resolvers to control their botnets, which is only a small step up from directly abusing the Emercoin DNS servers.

If OpenNIC already has an agreement with Spamhaus for blocking botnet domains, could the Emercoin DNS "window" servers adopt a similar filter? Anyone wanting an absolutely uncensored view of Emercoin names can simply use Emercoin directly, while the public DNS servers would not resolve domains known to be used for botnet control.

-- Jacob


Jonah Aragon wrote:
Katie,

I think you misunderstood his second proposal, he wants to only whitelist Tier 1 servers, and then the Tier 2 resolvers will slave from them (which is current functionality on the srvzone script most people use anyways, as far as I know) rather than Emercoin’s own servers. That seems like a much more reasonable request, since Tier 1 servers are generally unchanging, and as such the whitelist would be relatively manageable.
Jonah

On Sun, Jun 10, 2018 at 2:43 PM Katie Holly <opennic AT lists.dedilink.eu <mailto:opennic AT lists.dedilink.eu>> wrote:

Hi Oleg,

OpenNIC has an active agreement with Spamhaus that they are
allowed to feed one of our blacklists (see [0] for more
information) that Tier 2 operators can use to block domains solely
used for botnet control or other bad things. This was done for
other .bit domains that were used for controlling botnets (see [1}
for example)

Tier 1 servers are, as far as I know, under no circumstances
allowed to block any kind of domain or IP address. Such censorship
would immediately cause your Tier 1 server to be removed from the
root zone and replaced by another volunteers server.

If do not want to or, more specifically, can not continue serving
an uncensored view of the Emercoin zones, please let us know and
we'll find a volunteer to run a Tier 1 server as a replacement to
yours. This is, at least from what I can see, the only viable
solution.

1. Wouldn't be a good solution IMHO - Yes, it would decentralize
the network a bit but block Tier 2 operators from continuing to
run their root-hint-only servers from which there are many.
Example for our anycast network: Servers do not store any
information on hard disks other than static files pushed into
Docker container images on build time and they are not allowed to
write to disk and have to use a small (10MB size) tmpfs directory
to keep their dynamic data stored.

2. DNS resolvers do not always use the same IP address for backend
queries and frontend service. A DNS server might be reachable at
8.8.8.8 or 185.121.177.177 but whenever it needs to query an
authoritative DNS server for more information, it used a backend
IP address, for 8.8.8.8 that would be a lot of /24 networks [2],
for 185.121.177.177 that would be a lot of IP addresses, fast
moving IP addresses since we utilize cloud services a lot and you
wouldn't be able to keep up with the amount of IP address changes
involved in this, this is a problem specific to how anycast works
and we have seen a couple users hopping onto that anycast service
train recently to host their Tier 2.

Another "solution" I see, which wouldn't be very viable, is to
drop the requirement for Tier 2 servers to resolve any crypto
domains and allow them to use your suggested solution in point 1
if they want to offer crypto TLDs for their users.

Best regards

Katie Holly

[0] https://wiki.opennic.org/api/blacklist
[1] https://www.spamhaus.org/sbl/query/SBL325026
[2]

https://developers.google.com/speed/public-dns/faq#locations_of_ip_address_ranges_google_public_dns_uses_to_send_queries

On 06/10/2018 08:21 PM, Oleg Khovayko wrote:
> Hi,
>
> I am representing Emercoin, which has successful peering with
OpenNIC for years.
>
> However, recently I see, our servers seed1 and seed2, where
OpenNIC requests info about zones .coin/.emc/.bazar/.lib, started
used to control botnets.
> There is many requests from different IPs for same domain name,
fields A/TXT.
> I analyzed field TXT in some EmerDNS recors, for example:
dns:refereefitter.lib
> And found there - there is some encrypted strings, seems like
command to botnet.
> This article contains more information:
>

https://www.fireeye.com/blog/threat-research/2018/04/cryptocurrencies-cyber-crime-blockchain-infrastructure-use.html
>
> I would like continue peering, but do not want to serve a
criminal botnets.
>
> I see 2 ways, how to mitigate this issue:
>
> 1. Each Tier1 OpenNIC will setup local Emer node, and perform
peering to the localhost. And we will just discontinue our peering
services.
> Pros: Quick resolving, best security
> Cons: Needed ~1G HDD and 300MB RAM to running process.
>
> 2. We can add IP filters to our seed1/seed2, and ban all IPs,
but 10 Tier 1 OpenNIC servers.
> Pros: Nothing needed to do on OpenNIC side
> Cons: Dependence on network, bigger latencies.
>
> So, I have questions:
> 1. If we will add DNS-filters, which includes Tier1 servers - is
this enough to continue peering with option 2?
> 2. Is this possible to move to option 1, when OpenNIC keeps
local resolver?
>
> Thanks,
> Oleg
>
>
>
>
>
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