tor-dev September 2015

tor-dev@lists.torproject.org

61 participants
65 discussions

Re: [tor-dev] Should cloud-hosted relays be rejected?
by tordev123＠Safe-mail.net 02 Sep '15

02 Sep '15

From: Sharif Olorin <sio(a)tesser.org> To: tor-dev <tor-dev(a)lists.torproject.org> Subject: Re: [tor-dev] Should cloud-hosted relays be rejected? Date: Wed, 02 Sep 2015 08:32:58 +0000 > > I'm not talking about those providers hosting exit nodes. I'm talking about general web sites and resources hosted by them and the traffic that goes there. > > I'm confused. You're worried about people hosting clearnet websites > with cloud hosting providers? Or non-exit relays? Correlation between all kinds of relay traffic and clearnet traffic. Entry traffic would be the worst, allowing end-to-end correlation.

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Re: [tor-dev] Should cloud-hosted relays be rejected?
by tordev123＠Safe-mail.net 02 Sep '15

02 Sep '15

From: nusenu <nusenu(a)openmailbox.org> To: tor-dev(a)lists.torproject.org Subject: Re: [tor-dev] Should cloud-hosted relays be rejected? Date: Tue, 1 Sep 2015 19:23:35 +0200 > > It has other benefits. Those big providers see a huge amount of exit > > traffic and can potentially do correlation against that. > > I disagree on 'huge'. > If you worry about i.e. Amazon hosting to much exit bandwidth you have > to worry about many other* ASes first, and even then, banning them all > completely (exit prob = 0) isn't probably a wise strategy. I'm not talking about those providers hosting exit nodes. I'm talking about general web sites and resources hosted by them and the traffic that goes there.

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Re: [tor-dev] Should cloud-hosted relays be rejected?
by tordev123＠Safe-mail.net 01 Sep '15

01 Sep '15

From: nusenu <nusenu(a)openmailbox.org> To: tor-dev(a)lists.torproject.org Subject: Re: [tor-dev] Should cloud-hosted relays be rejected? Date: Tue, 1 Sep 2015 00:58:05 +0200 > I don't think banning GCE, AWS and MS Azure is an efficient method to > significantly increase the cost of attacks because it is trivial for an > attacker to quickly spin up "a large number of disposable machines" at > other ISPs as well. It has other benefits. Those big providers see a huge amount of exit traffic and can potentially do correlation against that.

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Should cloud-hosted relays be rejected?
by Philipp Winter 01 Sep '15

01 Sep '15

We sometimes see attacks from relays that are hosted on cloud platforms. I have been wondering if the benefit of having cloud-hosted relays outweighs the abuse we see from them. To get an idea of the benefit, I analysed the bandwidth that is contributed by cloud-hosted relays. I first obtained the network blocks owned by three cloud providers (Amazon AWS, Google Cloud, Microsoft Azure), and determined the percent of bandwidth they contributed in July 2015. The results show that there were typically ~200 cloud-hosted relays online: <https://nymity.ch/sybilhunting/png/cloud-hosted_relays_2015-07.png> The spike shortly after hour 200 was caused by a lot of Amazon relays named "DenkoNet". The spike at the very beginning was caused by a number of relays that might very well belong together, too, based on their uptime pattern. What counts, however, is bandwidth. Here's the total bandwidth fraction contributed by cloud-hosted relays over July 2015: <https://nymity.ch/sybilhunting/png/cloud-hosted_bandwidth_2015-07.png> There were no Google Cloud relays to contribute any bandwidth. Amazon AWS-powered relays contributed the majority of bandwidth, followed by Microsoft Azure-powered relays. Here's a summary of the time series in percent: Min. Mean Median Max. 0.2% 0.8% 0.79% 1.5% In an average consensus in July 2015, cloud-hosted relays contributed only around 0.8% of bandwidth. Note, however, that this is just a lower bound. The netblocks I used for the analysis could have changed, and I didn't consider providers other than Google, Amazon, and Microsoft. There are also cloud-hosted bridges. Tor Cloud, however, has shut down, and the number of EC2 bridges is declining: <https://metrics.torproject.org/cloudbridges.html?graph=cloudbridges&start=2…> The harm caused by cloud-hosted relays is more difficult to quantify. Getting rid of them also wouldn't mean getting rid of any attacks. At best, attackers would have to jump through more hoops. If we were to decide to permanently reject cloud-hosted relays, we would have to obtain the netblocks that are periodically published by all three (and perhaps more) cloud providers: <https://docs.aws.amazon.com/general/latest/gr/aws-ip-ranges.html> <https://msdn.microsoft.com/en-us/library/azure/Dn175718.aspx> <https://cloud.google.com/appengine/kb/general?hl=en#static-ip> Note that this should be done periodically because the netblocks are subject to change. Cheers, Philipp

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Where are the GetTor downloads (e.g. GitHub)?
by David Fifield 01 Sep '15

01 Sep '15

Someone IRL asked me about mirrored downloads of Tor Browser on services like GitHub. I know that such services are planned (or already implemented?) for GetTor, and I know about these tickets: Integrate cloud services that are not blocked in mainland China https://bugs.torproject.org/14114 Automate upload of latest Tor Browser to cloud services https://bugs.torproject.org/14744 Script to upload Tor Browser to Github https://bugs.torproject.org/14835 My question is, is there a static URL on GitHub or similar that has the latest downloads? That is, one that people can access even without having used GetTor? Such a URL would be more useful than a typical mirror for many users. I was referred to Lantern's GitHub download page for comparison: https://github.com/getlantern/lantern/releases/tag/latest It has direct links to downloads under githubusercontent.com: https://raw.githubusercontent.com/getlantern/lantern-binaries/master/lanter… https://raw.githubusercontent.com/getlantern/lantern-binaries/master/lanter… https://raw.githubusercontent.com/getlantern/lantern-binaries/master/lanter…

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tor-dev September 2015