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Sunburst

Bizarre and unusual uses of DNS

Rule 53: If you can think of it, someone's done it in the DNS

Peter Lowe

Principal Security Researcher | DNSFilter

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whoami

  • Peter Lowe
  • Principal Security Researcher at DNSFilter
  • Open for work

  • I spend a lot of time thinking about DNS and malware techniques

  • You might know me from my blocklist for ads and trackers at pgl.yoyo.org

  • Terrible, absolutely terrible, at slides

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Potential Titles

  • How I Learned To Stop Worrying And Love DNS

  • The things people do with DNS

  • 20 Wacky DNS Tricks - #5 will SHOCK YOU

  • DNS Museum*

  • Went with something descriptive in the end

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What

DNS in 2 minutes

  • DNS is an always available, highly resilient, incredibly fast, fundamental part of the internet.

  • … so of course people have done some interesting things with it.

  • "Questions" are sent to resolvers, which return "answers" - the records you're looking for. These are normally domains.

  • It's often called the "phone book of the internet" - you look up a domain and get records back about it (not just IPs, but TXT records, MX records, etc.)�
  • This makes it a general records system.

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Why

Not my fault

  • It's John Todd's fault really

  • This became a Twitter thread

  • DNS Abuse SIG work - first.org/global/sigs/dns

  • Rule 34 implies that thinking of something brings it into existence…

  • … so let's not suggest anything too out there

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Caveats

And notes

  • Most not around anymore

  • Thought I'd have more time for this talk

  • Links at the end

  • Really, I'm terrible at slides, I hate doing them

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Traceroutes

OK, so maybe not 100% DNS…

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Traceroutes

Star Wars

From Ryan Werber at beagle.net in Feb 11th 2013

Down because of DDoS

IPv6 versions popped up

Gone but not forgotten

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Traceroutes

hand.bb0.nl

Interesting extension using IPv6 - apparently there's more if you increase hops

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Traceroutes

Euro 2020

Sebastian Haas' "fakert" that creates a TUN device

IP range routed to where the fakert is running

@_sehaas on Twitter

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Traceroutes

makerforce.io

By Ambrose Chua

To the tune of "American Pie"

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Traceroutes

bad.horse

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Traceroutes

bad.horse

From Dr Horrible's Sing-Along

Bonus: cert chain from signed.bad.horse

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Traceroutes

Christmas

Ho

Ho

Ho

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Tools and Toys

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Tools and Toys

Calculator

Sadly not around anymore

There's a reverse Polish calculator out there as well

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Tools and Toys

"My IP"

OpenDNS

Google

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Tools and Toys

"My IP"

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Tools and Toys

IP to ASN

From Team Cymru - similar to Whois but faster

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Tools and Toys

Postcodes

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Tools and Toys

dns.toys

From Kailash Nadh, CTO of Zerodha

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Tools and Toys

Geocaching

From Sebastian Haas:

Mockapetris himself wasn't involved in the geocache. "Mockapetris_1876" is just a hint to DNS and RFC 1876 ;)

The cache is maintained by me.

To solve the complete riddle you have to execute multiple queries (TXT, AAAA, PTR, LOC). You can find the solution in the screenshot.

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Tools and Toys

Text adventure

By Craig Mayhew, @craigmayhew

Uses round robin DNS for chance-based actions

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Tools and Toys

Drink

From Stéphane Bortzmeyer, @bortzmeyer

Amazing general purpose dynamic DNS server

Try 2+2.op.dyn.bortzmeyer.fr, LOC and URI query types on random.dyn.bortzmeyer.fr

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Tunneling

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Tunneling

General idea

https://www.daemon.be/maarten/dnstunnel.html

Discussed on Slashdot back in 2000

Any record types

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Tunneling

Wikipedia

David Leadbetter

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Tunneling

Blogging

Add TXT records to "publish" a post

By Harshad Sharm - trying to "break coder's block"

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Tunneling

IP over DNS

Erik Eckman - @yarrick on GitHub

IPv4 only inside the tunnel, but server can listen on IPv6

Iodine has the atomic number 53

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Tunneling

HTTP over DNS

Jessie Li, @veggiedefender on GitHub

HTTP over DNS over HTTPS?

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Tunneling

VPN over DNS

"Contains ads"

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Tunneling

dnscat2

Iagox86 on GitHub, or "Ron"

Doesn't need a domain

Looks exactly like normal DNS traffic

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And more

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Bigger things

DNS for config

Corey Quinn

Using Route 53 for config management

@quinnypig on Twitter

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Bigger things

Brands

BIMI records

Really just TXT records starting _bimi

https://bimi.agari.com/

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Bigger things

Contacts DB

"Free, unlimited, unrestricted access to data about every company in the UK*"

npm modules, developer docs

Numprotocol.com

NUM technology

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Bigger things

Key-value store

Generic service offered to allow people to set and retrieve values

Not sure who's behind this!

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Bigger things

DNSFS

Ben Cox, benjojo.co.uk

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Bigger things

MP3s

One use of DNSFS…

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Links

https://dnsfilter.com/ - DNSFilter

https://github.com/sehaas/fakert - Sebastian Haas' fakert

https://beaglenetworks.net/post/42707829171/star-wars-traceroute - Star Wars traceroute

https://dgl.cx/wikipedia-dns - Wikipedia over DNS

https://www.youtube.com/watch?v=_y36fG2Oba0 - The Day The Router Died

https://www.youtube.com/watch?v=O03k0DV2m1k - Bad Horse

https://asciinema.org/a/15020 - Christmas traceroute

https://team-cymru.com/community-services/ip-asn-mapping/#dns - IP to ASN mapping

https://www.cambus.net/interesting-dns-hacks/ - few things including the calculator, My IP

https://jpmens.net/2020/10/04/airports-of-the-world/ - Airports

https://github.com/gryphius/ch-loc - Oli Schacher's Swiss location stuff

https://www.daemon.be/maarten/dnstunnel.html - Discussion of DNS tunneling

https://coord.info/GC615NM - Geocache

https://github.com/craigmayhew/dns-adventure-game - text adventure over DNS

https://github.com/hiway/txtrex - blogging via DNS (Harshad Sharma - @hiway)

https://gist.github.com/Manawyrm/718cf8ab6ba59ba95d9743d01b1763dd - MP3 streaming

https://github.com/yarrick/iodine - iodine - IP over DNS

https://github.com/veggiedefender/browsertunnel - HTTP over DNS

https://www.lastweekinaws.com/podcast/aws-morning-brief/whiteboard-confessional-route-53-db/ - DNS for config management

https://play.google.com/store/apps/details?id=com.in.troiddns - SlowDNS - VPN over DNS

https://dnskv.com/ - DNS Key Value Storage

https://github.com/iagox86/dnscat2 - dnscat2

https://bimi.agari.com/ - Brand Indicator Records

https://tools.ietf.org/id/draft-blank-ietf-bimi-00.html - BIMI draft

https://www.num.uk/ - num.uk business

https://www.numprotocol.com/ - the NUM protocol

https://github.com/benjojo/dnsfs - DNSFS

https://xkcd.com/1361/

https://team-cymru.com/community-services/ip-asn-mapping/#dns - IP to ASN mapping

https://www.bortzmeyer.org/drink.html - Drink DNS server

https://github.com/pgl/rule53 - Rule53 list on GitHub

https://twitter.com/pgl/status/1405614755000295427 - Twitter thread

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Questions?

Principal Museum of DNS Curator Security Researcher @ DNSFilter

Open for work

twitter.com/pglinfosec.exchange/@pgl

peter@dnsfilter.com / pgl@yoyo.org