Running Software in Albuquerque to Measure Censorship Anywhere - - PowerPoint PPT Presentation

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Running Software in Albuquerque to Measure Censorship Anywhere - - PowerPoint PPT Presentation

Feb 18, 2023 441 likes •717 views

Running Software in Albuquerque to Measure Censorship Anywhere Jeffrey Knockel Roya Ensafi Jedidiah Crandall Computer Science Department University of New Mexico When will Desert Storm invasion begin? No access to Pentagon Watch Dominos

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Running Software in Albuquerque to Measure Censorship Anywhere

Jeffrey Knockel Roya Ensafi Jedidiah Crandall Computer Science Department University of New Mexico

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When will Desert Storm invasion begin?

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No access to Pentagon

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Watch Dominos outside Pentagon

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Pentagon deliveries normally

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Night before an invasion

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Moral of the story

We can measure what is happening in a thing without being in that thing

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Question

Albuquerque Server Can clients connect to the server? Clients

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TCP Connection

Albuquerque Server Clients SYN SYNACK ACK

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Measurement

  • Run measurement software over there
  • Problem: cannot get software in there
  • Or:

– Not in the right city – Not right now

  • We don't need measurement software on

client, on server, or in between

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Client

  • Find client with globally incrementing IP ID
  • Windows XP, FreeBSD, etc. globally increment

this ID

IP Header Version / IHL / TOS Length ID Flags / Fragment Offset TTL / Protocol Checksum Source IP Destination IP

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Measure # of packets sent

  • Ping every second
  • 1006, 1007, 1008, 1009…

– 1, 1, 1… none sent

  • 3003, 3007, 3012, 3016…

– 4, 5, 4… some sent

  • 4000, 5000, 6200, 7300…

– 1000, 1200, 1100… lots sent

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Experiment

Albuquerque Server Client Forged SYN

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No censorship (+1)

Albuquerque Server Client Forged SYN SYNACK RST

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Server → Client censored (+0)

Albuquerque Server Client Forged SYN SYNACK SYNACK …

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Client → Server censored (+>1)

Albuquerque Server Client Forged SYN SYNACK RST SYNACK RST …

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ARIMA time series

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Iterative outlier removal

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Intervention analysis

Server → Client No censorship 5

Client → Server

15

Measured intervention: 15.1 Client → Server filtering!

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Ethical concerns

← Decrease clarity Decrease karma → Can clients sending RST's get them hurt? Ethical Knob

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Future

  • Gathering data
  • Using other shared finite resources

– Reassembly buffers – …

  • Other censorship

– DNS – DPI – …

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SpookyScan

Spooky scanning at a distance http://spookyscan.cs.unm.edu

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SpookyScan

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SpookyScan

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SpookyScan

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Acknowledgments

This material is based upon work supported by the U.S. National Science Foundation under Grant Nos. 0844880, 0905177, and 1017602. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the U.S. National Science Foundation.