- anti-censorship-team - lists.torproject.org

TurboTunnel Packet Scheduler Tips and Traffic Analysis Benefits
by Mike Perry 31 Mar '21

31 Mar '21

Hi all, I recently posted a draft proposal for traffic splitting for Tor: https://gitlab.torproject.org/tpo/core/torspec/-/blob/master/proposals/329-… It has similar properties as TurboTunnel, but I put quite a bit of work and consulted with several TCP and multipath TCP researchers to develop the packet scheduling algorithms defined in Section 3: https://gitlab.torproject.org/tpo/core/torspec/-/blob/master/proposals/329-… You may be interested in adopting those algorithms, if possible. There are variants that optimize for latency, throughput, or both in combination. The proposal also supports resumption of closed circuits. I am writing this mail because while these things are nice, resumption in particular does not defend against all classes of issues I am worried about with respect to confirmation attacks from closing or blocking connections, particularly onion service connections: https://gitlab.torproject.org/tpo/core/torspec/-/blob/master/proposals/329-… Briefly, if an adversary suspects an onion service is in use at a particular guard, it can make a circuit to that onion service, hold it open, and then close TCP connections of that guard to see if the circuit closes. This can even be done on the side with TCP RST injection, and possibly even blindly with brute force RST spoofing and spamming, if a good enough guess can be made about the IP address range of the service. Worse, in this case, the resumption I specified for Conflux does not help here, because this adversary will see the service's resumption attempt, and use that for confirmation instead of circuit close. TurboTunnel's resumption and automatic bridge discovery and replacement should greatly mitigate this attack, because it happens at a layer that is not necessarily controlled by the adversary, and thus resumption is mostly invisible to them (save for delay, which Cecylia is working on minimizing). Additionally, since traffic splitting has been shown to help against website fingerprinting, it stands to reason that doing traffic splitting at multiple layers and multiple endpoints may actually be better than doing it at just one layer, and costs us little-to-nothing in terms of overhead: https://www.comsys.rwth-aachen.de/fileadmin/papers/2020/2020-delacadena-tra… So please, keep on improving TurboTunnel! And let's compare notes about what we learn! Looking forward to obfs4 TurboTunnel, too! -- Mike Perry

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Ansible role that installs snowflake proxy on Debian
by Jacobo Nájera 17 Mar '21

17 Mar '21

Hi, I wrote an ansible role to install snowflake proxy on Debian Buster. I will extend its support to Fedora and Ubuntu and improvements soon. https://galaxy.ansible.com/nvjacobo/snowflake Repo: https://github.com/nvjacobo/snowflake Feedback is welcome Thanks, Jacobo

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No time change for the anti-censorship meeting
by Cecylia Bocovich 17 Mar '21

17 Mar '21

Hey everyone, We can discuss this at the meeting, but I'd like to keep the meeting time at 16 UTC regardless of the time change in places that recognize a difference between daylight savings and standard time. So, if you are in the US or Canada our weekly meeting will be at a different wall clock time. But it will be at the same time in UTC :) Hopefully see you there! Cecylia

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Next anti-censorship reading group: 4 March 2021
by Cecylia Bocovich 01 Mar '21

01 Mar '21

Hey everyone! We will discuss "Investigating Large Scale HTTPS Interception in Kazakhstan" this week at our team meeting on 2021-03-04, at 16 UTC. Relevant links: - https://censoredplanet.org/assets/Kazakhstan.pdf - https://censoredplanet.org/kazakhstan Questions to ask and goals to have: - What can we learn from this work? - Are there immediate actions we can take based on this work? - Are there long-term actions we can take based on this work? - Is there future work that we want to call out, in hopes that others will pick it up? Hope to see you all there! Cecylia

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Next anti-censorship reading group: 21 January 2021
by Cecylia Bocovich 20 Jan '21

20 Jan '21

Hey everyone! We will discuss "Early Detection of Censorship Events with Psiphon Network Data" two weeks from today at our team meeting on 2021-01-21, at 16 UTC. Paper link: https://tics.site/proceedings/2019a/icn_2019_7_10_38005.pdf Questions to ask and goals to have: - What can we learn from this work? - Are there immediate actions we can take based on this work? - Are there long-term actions we can take based on this work? - Is there future work that we want to call out, in hopes that others will pick it up? Hope to see you all there! Cecylia

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DDoS on Greenhost, may affect Snowflake
by David Fifield 23 Dec '20

23 Dec '20

Greenhost sent an email saying that since last 2020-12-17, there has been a DDoS attack against their infrastructure. This may affect Snowflake, because the broker and bridge are hosted by Greenhost in Amsterdam. > Please bear with us as Greenhost and the eclips.is platform are > suffering from some of the largest DDoS attacks we have faced. > > Between Thursday and now we have seen targeted attacks on one of our > users and directly at Greenhost. > > Our upstream provider in Miami has unfortunately completely dropped > the eclips.is infrastruccture routing as they could not withstand the > attacks. We are working to put that connectivity back up as we speak. > > The situation in Amsterdam is more under our control, and both > Eclips.is and Greenhost networks are available as of writing. 2020-12-17 09:10 outage caused by a major DDOS attack https://status.greenhost.net/incidents/19 > Since 10:10 CET, we have been experiencing outage caused by a major > DDOS attack. > > All VPSes, webhosting and emailservers were affected by this outage. > > We have deflected the attack and worked to recover all systems. 2020-12-20 15:00 Repeated DDoS attacks on our infrastructure https://status.greenhost.net/incidents/20 > After the DDoS attack last Thursday we did see recurring attacks of > increasing magnitude on our infrastructure. We are working through the > weekend with our technical service providers to increase resilience of > our network. We will update you as the situation progresses. At this > point our services are operational.

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Join the Minima community!
by Ryan Hennebry 14 Dec '20

14 Dec '20

Hi Tor Community, I’m the Community Manager of Minima, a cryptocurrency project based in London. Minima is a PoW base-layer blockchain protocol with a novel design, that runs entirely on mobile devices. Since every user runs a full node that validates and constructs the chain via an app, the protocol will be able to reach a user base not yet possible with any other blockchain protocol. This will allow our network to be as decentralised as possible, ultimately providing individuals a peer-to-peer censorship-resistant network for the transfer information and value. Our founder and lead developer Paddy Cerri built the Minima blockchain, and we are now entering testnet phase. Since Paddy’s true vision is to build a network where individuals have the freedom to send information and value without censorship, I thought that our protocol may be of interest to you. I wondered if any of you would be interested in helping us build censorship-resistant applications on the Minima protocol, debugging our code, or simply joining our community and learn more about crypto. I would love for you to join our discord community if you’re interested: https://discord.gg/SgvQ6mc Also, here are some resources that will give you more insight into Minima & Paddy: https://minima.global/blog/freedom https://minima.global/blog/blockchains-in-a-bitcoin-world-by-paddy-cerri-at… Thank you for your time and I look forward to meeting you all. Best, Ryan Hennebry / Community Manager ryan.hennebry(a)minima.global / +44 (0) 751 0989 043 Minima Unter Altstadt 28, 6300 Zug (Switzerland) 14-18 Great Titchfield Street, London, W1W8BD (UK) www.minima.global

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Next anti-censorship reading group: 3 Dec 2020
by Cecylia Bocovich 19 Nov '20

19 Nov '20

Hey everyone! We will discuss "Poking a Hole in the Wall: Efficient Censorship-Resistant Internet Communications by Parasitizing on WebRTC" two weeks from today at our team meeting on 2020-12-03, at 16 UTC. Paper link: https://dl.acm.org/doi/pdf/10.1145/3372297.3417874 Questions to ask and goals to have: - What can we learn from this work? - Are there immediate actions we can take based on this work? - Are there long-term actions we can take based on this work? - Is there future work that we want to call out, in hopes that others will pick it up? Hope to see you all there! Cecylia

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Next anti-censorship reading group, 12 Nov 2020
by Cecylia Bocovich 09 Nov '20

09 Nov '20

Hey everyone! We will discuss "The use of TLS in Censorship Circumvention" at our next team meeting on 2020-11-12, at 16 UTC. Paper link: https://tlsfingerprint.io/static/frolov2019.pdf Questions to ask and goals to have: - What aspects of the paper are questionable? - Are there immediate actions we can take based on this work? - Are there long-term actions we can take based on this work? - Is there future work that we want to call out, in hopes that others will pick it up? Hope to see you all there! Cecylia

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Anti-censorship meeting notes, 1 October 2020
by Cecylia Bocovich 05 Oct '20

05 Oct '20

Hey everyone! Here are the meeting logs: http://meetbot.debian.net/tor-meeting/2020/tor-meeting.2020-10-01-15.58.html And the meeting pad: Anti-censorship work meeting pad -------------------------------- Next meeting: Thursday October 1st 16:00 UTC Weekly meetings, every Thursday at 16:00 UTC, in #tor-meeting at OFTC (channel is logged while meetings are in progress) == Goal of this meeting == Weekly checkin about the status of anti-censorship work at Tor. Coordinate collaboration between people/teams on anti-censorship at Tor. == Links to Useful documents == Our anti-censorship roadmap: Roadmap: https://gitlab.torproject.org/groups/tpo/anti-censorship/-/boards The anti-censorship team's wiki page: https://gitlab.torproject.org/tpo/anti-censorship/team/-/wikis/home Past meeting notes can be found at: https://lists.torproject.org/pipermail/tor-project/ Tickets that need reviews: from sponsors we are working on: All needs review tickets: https://gitlab.torproject.org/groups/tpo/anti-censorship/-/merge_requests?s… Sponsor 30 https://gitlab.torproject.org/groups/tpo/-/milestones/4 https://gitlab.torproject.org/groups/tpo/-/milestones/7 https://gitlab.torproject.org/groups/tpo/-/milestones/5 https://gitlab.torproject.org/groups/tpo/-/milestones/6 Sponsor 28 must-do tickets: https://gitlab.torproject.org/groups/tpo/-/milestones/10 possible tickets: https://gitlab.torproject.org/groups/tpo/-/issues?scope=all&utf8=%E2%9C%93&… Anti-censorship related tickets that we want other teams to fix: https://pad.riseup.net/p/tor-anti-censorship-tickets-keep <-- it will be moved into gitlab with TPO labels Public bug-reporting pad: https://pad.riseup.net/p/tor-anti-censorship-bugs-keep == Announcements == Kyle MacMillan, Jordan Holland, and Prateek Mittal published a report on Snowflake distinguishability. https://arxiv.org/abs/2008.03254 == Discussion == How can we improve our terminology for bridges? https://gitlab.torproject.org/tpo/anti-censorship/rdsys/-/issues/8 == Actions == == Interesting links == == Reading group == We will discuss "" on Questions to ask and goals to have: What aspects of the paper are questionable? Are there immediate actions we can take based on this work? Are there long-term actions we can take based on this work? Is there future work that we want to call out, in hopes that others will pick it up? == Updates == Name: This week: - What you worked on this week. Next week: - What you are planning to work on next week. Help with: - Something you need help with. phw: This week (2020-10-01): Reviewed antonela's Tor Browser design proposal for better circumvention. https://gitlab.torproject.org/tpo/applications/tor-browser-spec/-/issues/40… Helping out with DRL grant application. More work on rdsys; thinking about how feedback loop for blocked bridges should be handled. Wrapped up bridgestrap MVP. Next week: Help with: cecylia (cohosh): last updated 2020-10-01 Last week: - finished preparations for next sponsor 28 evaluation of snowflake - reviewed bridgedb#31871 - reviewed anti-censorship/trac#31874 - implemented fix for snowflake#33157 - checked on tests running for snowflake#32657 This week: - revisit multiplexing ticket - revisit NAT-punching problems for symmetric NATs - write up collected snowflake throughput data from last month and draw some useful conclusions - catch up on rdsys work - follow up with guardian project on their snowflake integration work Needs help with: - review of snowflake!12 - review of snowflake-webext!4 juggy : This week: - Got very basic "suggested readings" list up and running here : https://jugheadjones10.github.io/anti-censorship-reading/ Next week: - Keep studying BridgeDB to write architectural overview Help with: - Open issues here (https://github.com/jugheadjones10/anti-censorship-reading ) for papers/resources/readings that you think might be useful for newcomers arlolra: 2020-06-11 Last week: - Next week: - follow ups to #33365 - start on #31201 Help with: - dcf: 2020-10-01 Last week: - merged a patch from Peter Gerber to expand the set of IP addresses Snowflake considers local (for stripping from SDP offers) https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snow… - Azure CDN bookkeeping Next week: Help with: - is anything further needed for Azure CDN account access? https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snow… Antonela: 2020-08-27 This week: - Wrapping Babatunde's research on the use of circumvention tools during internet censorship in Africa. Wrapping Personas for s30 with it. For september: - We are planning interviews with users in China to run our bridges discovery issues script in real time. We discussed to include TBA + snowflake as a task for users to run over a week or two and report back. https://gitlab.torproject.org/tpo/ux/research/-/issues/4 - I still have bridges.tpo to lektor issue open - More work on UX/UI for TB 10.0/10.5 - Review Salmon related tickets (im late with it!) agix:2020-10-01 Last week: -Still on #34218 (Should finish it soon though) -Started with #5 (rdsys) -Read this weeks paper Next week: -Finish both tickets Help with: - hanneloresx: 2020-09-17 Last week: - Start on #33727 - Continue investigating and respond to comments on #32117 Next week: - Continue last week's work. Help with: - thymbahutymba: 2020-04-02 Last week: - CI/CD pipeline for multiarch docker images, which has a problem with the apt tor version even though the apt repository have been changed into the Dockerfile. Next week: Help with: HashikD: 2020-08-27 This week: - GSoC blog Next week: - Away on exams Help with: -

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