
Possible upcoming attempts to disable the Tor network - dewey
https://blog.torproject.org/blog/possible-upcoming-attempts-disable-tor-network
======
cjbprime
(Disclaimer: I am not affiliated with Tor, I'm just poking around their source
code. My conclusions may be totally wrong.)

You can see the list of trusted directory authorities in Tor's
src/or/config.c:

[https://gitweb.torproject.org/tor.git/tree/src/or/config.c#n...](https://gitweb.torproject.org/tor.git/tree/src/or/config.c#n820)

There are nine of them (actually ten, but one is just for bridges), so you'd
have to disrupt at least five of them to prevent them forming a majority vote
on consensus together. Looks like the countries that own the IP address
allocations for each dirauth are:

Austria, Germany, Germany, Holland, Holland, Sweden, US, US, US

If the above is all correct, a US<->Germany collaboration - to pick the
largest set from two countries - would be one way to cause a large problem.

~~~
higherpurpose
Could the Tor Project sue against those seizures?

~~~
chippy
Would suing repair the damage? How long would it take? Could it actually be a
criminal act?

------
declan
This is a very big deal if it happens. Roger's linked post on the Tor site
talks about "seizure" of directory authority servers; only government
authorities would have that power. In the U.S. that would typically happens
only after a court grants a seizure order, which would be under seal at this
stage.

Of the countries where the servers are located, the U.S. has the most extreme
copyright laws, which means, sadly, FedGov is the leading candidate to be
behind any possible seizure.

It would be interesting if an enterprising journalist were to ask MIT, SF-
based Applied Operations, and RiseUp if they've been contacted by law
enforcement on this matter. Those organizations host some of the U.S.-based
servers. RiseUp has a warrant canary but it hasn't been updated recently:
[https://help.riseup.net/en/canary](https://help.riseup.net/en/canary)

Of course we don't know what actually is going on and it all may be (I hope!)
a false alarm.

PS: If multiple governments cooperate and a majority of servers are taken
down, what happens to Tor after the consensus interval expires? I don't know;
maybe someone more familiar with Tor does. The consensus interval was changed
to 72 hours a few years ago:
[https://trac.torproject.org/projects/tor/ticket/7986](https://trac.torproject.org/projects/tor/ticket/7986)

PPS: Remember that FedGov's "copyright infringing" domain name seizures have
on occasion taken down non-infringing sites in error, as I wrote about here:
[http://www.cnet.com/news/dhs-abruptly-abandons-copyright-
sei...](http://www.cnet.com/news/dhs-abruptly-abandons-copyright-seizure-of-
hip-hop-blog/)

~~~
geographomics
Is it really that much of a big deal though?

I would expect that each authority server's configuration data is securely and
reliably backed up, so if the physical servers are seized, then a replacement
can be fairly easily provisioned. Maybe some operators will even have one
waiting on standby, in case of a normal hardware failure or similar.

Presumably the IP address space isn't being seized or otherwise disbanded, so
it could be dropped in exactly as specified in the hard-coded configuration -
that is, the same IP address and port.

Any ongoing and persistent impersonation of the server wouldn't be viable, as
the long-term directory authority identity keys are kept offline.

Maybe I'm missing something here but it sounds like more of a symbolic
violation, rather than a potentially catastrophic disabling event that brings
down Tor.

~~~
cjbprime
I think you're probably overestimating the portability of IP addresses, and
underestimating the coercive power of the organization that does the seize.

IP addresses are assigned to a network provider, not a customer. If I'm hosted
by a US provider and the FBI seizes my server, is that provider going to say
"sure, just spin up a new box on the old IP", or are they going to tell me to
get off their network? What if the FBI has an opinion on which decision the
provider should take? What if the FBI has an opinion on which action the
_directory operator_ should take?

~~~
pizzeys
> IP addresses are assigned to a network provider, not a customer.

Actually, they can be assigned to either. See:
[http://en.wikipedia.org/wiki/Provider-
independent_address_sp...](http://en.wikipedia.org/wiki/Provider-
independent_address_space)

------
discostrings
It's very interesting that the project has some advanced notice about a
threat.

My first guess would be that a nation has made some demands of the project
that the project won't comply with, and that country has suggested they will
seize the directory authority servers located inside it if the demands aren't
met soon. [Edit: a new comment by arma on the original story, "To be sure to
keep our source safe, we're not providing more details quite yet", makes this
seem less likely.]

Or perhaps an insider has leaked some plans to the project.

Along another line of thought, if the US government wanted to further
complicate online privacy, I imagine they'd choose a time like now, when
headlines about the "cyber intrusions" of 2014 are at a peak. I wonder what
other actors could have large enough power over their directory authority
servers for the project to post this message.

Edit: Indeed, from a post below by paralelogram [0] and by checking
[https://atlas.torproject.org](https://atlas.torproject.org) , it appears 4 of
9 are in the US. There are also two in Germany, one in the Netherlands (as
well as another there that is only for bridge relays), one in Austria, and one
in Sweden.

[0]
[https://news.ycombinator.com/item?id=8775009](https://news.ycombinator.com/item?id=8775009)

~~~
cjbprime
But taking out four nodes isn't enough to cause a full consensus outage.

~~~
deciplex
We still haven't discovered the thing that the US government can ask, that the
Swedish government will refuse. So I think they'll be able to get five.

------
robertfw
What ability does TOR have to operate in a decentralized manner without the
directory servers? Is that something that is possible now, or is it being
worked on, or is it even possible?

edit: this question was asked in the blog comments, here is arma's response

> There are a bunch of research papers looking at exactly this question. Check
> out
> [http://freehaven.net/anonbib/#usenix11-pirtor](http://freehaven.net/anonbib/#usenix11-pirtor)
> for one direction, and then [http://freehaven.net/anonbib/#wpes09-dht-
> attack](http://freehaven.net/anonbib/#wpes09-dht-attack)
> [http://freehaven.net/anonbib/#ccs09-shadowwalker](http://freehaven.net/anonbib/#ccs09-shadowwalker)
> [http://freehaven.net/anonbib/#ccs09-torsk](http://freehaven.net/anonbib/#ccs09-torsk)
> [http://freehaven.net/anonbib/#ccs10-lookup](http://freehaven.net/anonbib/#ccs10-lookup)
> for another direction to consider. The current situation is that nobody
> knows of a better design that is actually better in practice. The one we
> have is well-studied and has well-understood downsides, so I'm not eager to
> move to one that is poorly-studied and has poorly-understood downsides.

~~~
chrisfosterelli
Based on my understanding of the TOR network, it currently cannot function
without directory authorities. The directory authorities provide a signed list
of all of the TOR network relays, and that includes the set of encryption
certificates used for each relay and all of the configuration information
about it.

The TOR clients come hard coded with a list of directory authorities. Without
the ability to query the directory authorities they cannot find a usable TOR
route. I don't know if there is some caching involved, but if not then this
would effectively stop the network for anyone trying connect to TOR.

~~~
derefr
So why couldn't signed lists of relays just, say, float around on a DHT, with
a cache-and-forward model like Freenet, but where newer documents (provided
they're signed with the same key) will overwrite older documents in the same
cache slot?

Actually, to put it another way, Freenet is itself the optimal bootstrapping
mechanism for Tor. Maybe the two projects should merge, such that Tor would
effectively be an optimization over the specific case of two peers generating
and searching for one-another's signed Freenet documents (this effectively
being an IP tunnel already).

~~~
mike_hearn
It's already done that way. Tor relays cache signed consensus documents from
the directory authorities. It doesn't change the fact that you need some
trusted computers, somewhere, that give you an accurate view of the network.

~~~
StavrosK
Ah, so you need them for a trusted calculation, rather than for a trusted
static file. The latter would be easy to sign and store on a CDN.

------
d0mdo0ss
Someone posted a somewhat toxic but somewhat valid point, and the project
responded with more details about their 'source'. I add their response but it
may be best to read the original post.

To be sure to keep our source safe, we're not providing more details quite
yet.

But actually, we don't know many more details than the ones we posted. And as
for your 'why', that's an excellent question, and one we've been wrestling
with too. There are nine directory authorities, spread around the US and
Europe. If they're trying to hunt down particular Tor users, most possible
attacks on directory authorities would be unproductive, since those relays
don't know anything about what particular Tor users are doing.

Our previous plan had been to sit tight and hope nothing happens. Then we
realized that was a silly plan when we could do this one [post the warning]
instead.

------
mike_hearn
I doubt this will be a popular post, but I'll make it anyway.

If there are some seizures of directory authorities or other project
infrastructure, this won't be some totally unpredictable occurrence. It was
only about a month and a half ago that some relays were seized as part of a
general takedown against Tor hidden services. The Tor project posted this blog
in response:

[https://blog.torproject.org/blog/thoughts-and-concerns-
about...](https://blog.torproject.org/blog/thoughts-and-concerns-about-
operation-onymous)

That blog post convinced me to shut down my relay. The reason is, to an
ambitious prosecutor this blog post looks like:

"We view law enforcement operations as attacks and are looking for ways to
defeat them, because we are determined to shield the identities of our
criminal clients"

... which is exactly what resulted in the operators of the Silk Roads getting
arrested even though they were not personally selling drugs.

The blog post makes casual reference to the "enormous social value" of hidden
services and claim they're worried about "secret police repressing
dissidents", but doesn't cite any actual examples. Actually I've never heard
of a hidden service that has enormous social value - whilst there are a small
number of .onion addresses that aren't completely illegal or unethical, for
all the examples I know of the operators are not anonymous.

To police forces around the world who keep having investigations hit a dead
end because of Tor, going after the project directly will not seem very
different than going after services like Liberty Reserve. The people running
it are stating publicly that they will do their best to frustrate
investigations, and that is dangerously close to admitting participation in a
criminal conspiracy. Thin ice doesn't even begin to describe their current
situation.

~~~
olalonde
I agree that they are vastly inflating the utility of Tor for people in
repressive regimes given how easy it is to block Tor at an ISP level (e.g. Tor
is completely blocked in China).

~~~
ikawe
If you, like me, didn't know how Tor is being blocked in China:
[https://www.usenix.org/sites/default/files/conference/protec...](https://www.usenix.org/sites/default/files/conference/protected-
files/winter_foci12_slides.pdf)

Interestingly it's partially the same issue - the directory servers have
static IP's. ISP's are simply blocking traffic to these directory server IPs.
Without access to the directory servers, can you still use Tor?

Also see above article for thoughts on how to circumvent this mode of
censorship.

~~~
dsl
Tor has a network of unpublished bridges it provides via offline methods in
high risk countries. You can also request unpublished bridges via email [1].
Pluggable transports [2] allow your tor traffic to look like Skype or SSL.
These tools combined allow most of the "noble use cases" of tor to operate
without being hunted down.

1\.
[https://www.torproject.org/docs/bridges.html.en](https://www.torproject.org/docs/bridges.html.en)

2\.
[https://www.torproject.org/docs/bridges.html.en#PluggableTra...](https://www.torproject.org/docs/bridges.html.en#PluggableTransports)

------
jwcrux
Assuming it's a legal entity that will be performing these seizures, I'm
curious to know the case against these servers. To my (albeit somewhat
limited) knowledge of the Tor network, these DA's exist solely to maintain the
integrity and structure of the network, and to provide a list of known relays
to clients.

I also understand that this list of trusted DA's is hardcoded into Tor
clients. Since this is the case, I'd be curious how the network could be
restored if there is a coordinated action on these servers.

~~~
catshirt
"I also understand that this list of trusted DA's is hardcoded into Tor
clients"

forgive my ignorance, why would they do this in the first place? fear of MITM?

~~~
boklm
Because the clients need to get the list of nodes from somewhere.

You can read more about how this works at this URL:
[https://gitweb.torproject.org/torspec.git/tree/dir-
spec.txt](https://gitweb.torproject.org/torspec.git/tree/dir-spec.txt)

~~~
catshirt
just because they need a list of nodes doesn't mean they need to be hardcoded
into the client. the other option of course would be to fetch the list
remotely.

~~~
eli
From what? A directory directory server?

~~~
MichaelGG
From any peer? If the list is signed by a majority set of keys then it doesn't
matter how it gets distributed.

~~~
eli
Isn't finding a peer the original problem?

~~~
MichaelGG
Any Tor node could be a peer to distributed a signed piece of data.

~~~
eli
Yes, but how does one locate a tor node without a directory server?

~~~
MichaelGG
Maybe like Bittorrent DHT? The client could keep a cache of other known nodes.
You could share them on pastebin versus having them b only hard coded. You
could preloaded a hundred peer nodes, instead of 9 master nodes. It doesn't
strictly eliminate the problem, but it makes it less likely that one or two
governments can just shut it all down.

~~~
acebarry
This is kind of how i2p does it. Currently i2p has like 6 "reseed servers"
which bootstrap you into finding some other peers. Once you are connected to
the network you then can contact "floodfill" servers, which are essentially a
distributed form of the directory authorities. Floodfills are autonomously
chosen routers on the network, and distribute other nodes to whoever asks.

------
jgwest
Seems like somebody in the DoJ just decided that Tor's balance between geeky
CompSci curiosity and enabler of real-world criminal behavior has tipped too
far in the latter direction. The legal case has been ripe for a while-- after
all, Megaupload and many other networks have been disabled by the US
government for enabling significantly LESS serious criminality. Ummm...
world's biggest drug marketplace, anyone??? What's important to remember is
that the gov't can't just go in and seize the directory authority servers
willy-nilly. Instead, they must do it as part of a legal process against a
specific, identified target. In this case, the likely target is going to be
the Tor project itself and possibly the individuals leading it. The legal case
might ruffle a few techie feathers but only an insignificant portion of the
general public will care, and that portion can be mollified with the "stopping
the bad horrible criminals" routine.

~~~
sandworm
Those were not shutdown for "enabling" criminal activity. They were shut down
for actually doing criminal activity. With megaupload it was failure to abide
by the DMCA, with silk road it was handling money for/from drug dealers. I
cannot see how Tor has actually done anything criminal beyond what a thousand
other transitory service providers do every day.

~~~
rasz_pl
in case of megaupload it was totally ILLEGAL, using bogus charges

~~~
scandinavian
According to the internal emails the prosecutors got their hands on,
megaupload was paying out to the top uploaders, and megaupload showed
knowledge of what the uploads where. I can't stand commercial piracy.

[http://www.justice.gov/usao/vae/victimwitness/mega_files/Meg...](http://www.justice.gov/usao/vae/victimwitness/mega_files/Mega%20Evidence.pdf)

------
sandworm
If this turns out to be (1) real and (2) linked to the Sony fiasco, then North
Korea has triumphed. They have taken down two enemies in a single hack: a film
and an internet technology. That puts them ahead of the MPAA and the NSA
combined.

------
mortov
I think we can guess we're about to be told the North Koreans used TOR so
decisive action needs to be taken against the network as part of the
retaliation measures just announced.

------
click170
Is there anything that users can do to help with this? Donating money or
hosting, or running a Tor node?

There wasn't any info on the blog about what regular users can do to help with
this, if anything.

~~~
robertfw
The targeted servers are directory servers, which are not what the user runs.
AFAIK there is nothing that can be done short of supporting TOR through
donations, so they can focus on whatever needs to be done.

~~~
jloughry
You're right, so I sent the Tor Project a donation through paypal. They're a
U.S. 501(c)(3) non-profit organization.

------
nickodell
Does anyone have any more information?

What jurisdictions are these Directory Authorities located in?

~~~
paralelogram
193.23.244.244: Germany, Chaos Computer Club e.V.

194.109.206.212: Netherlands, XS4ALL Internet BV

154.35.32.5: United States, Cogent Communications

131.188.40.189: Germany, Friedrich Alexander Universitaet Erlangen Nuernberg

199.254.238.52: United States, Riseup Networks

171.25.193.9: Sweden, Foreningen for digitala fri- och rattigheter

128.31.0.34: United States, Massachusetts Institute of Technology

82.94.251.203: Netherlands, NAH6 BV

86.59.21.38: Austria, SILVER:SERVER GmbH

208.83.223.34: United States, Applied Operations, LLC

~~~
mindslight
There really is no Russia/China? Why are _all_ of the servers located within
the jurisdiction of USG?!

~~~
dsl
The United States may occasionally do some shady shit, but the Chinese will
frequently conduct blatant theft of intellectual property off your servers.
This is why very few tech companies will host within China proper.

~~~
mindslight
That's irrelevant when the entire purpose of directory servers is to propagate
signed and published information.

------
sandworm
Aside from the physical takedowns, expect a financial crackdown. Tor project
assets would be seized, Paypal accounts locked, and CC services withdrawn.

~~~
haakon
That would be almost too stupid, considering how Tor is financed in large by
U.S. government grants.

------
aburan28
The United States Government will fail because even if they were to
significantly disrupt the Tor network we'll pull out the Zero Knowledge Proofs
on them. We have the crypto and technology to build a super resilient Tor
replacement that they cannot do a single thing about. Tor is antiquated and I
personally hope they take it out because it's replacement will be 100x better.

~~~
josephagoss
Where is this 100x better replacement?

Lots of people around the world depend on the anonymity of Tor today and
having the Government take it out, whilst indirectly kick-starting the next
generation anonymity network is all and well for me and my armchair, but it's
going to be life threatening for many.

Until this 100x better solution exists Tor must be kept running at any cost,
many lives depend on it.

------
pc2g4d
Sounds like time to stand up some spare directory servers, preferably in
different legal jurisdictions than those currently represented.

------
guelo
I'm surprised they're able to talk about this, seems. Like the FBI would have
gone with a NSL (National Security Letter).

~~~
Havvy
They haven't been sent an NSL at the time of the writing of that post. They
don't have details on what the attack is, only that they think there is going
to be one.

------
justcommenting
the most recently restarted dirauths appear to run Tor 0.2.6.1-alpha-dev,
including four of the five US-based dirauths (moria1, Faravahar, urras,
dizum). gabelmoo, tor26, longclaw, Tonga, and maatuska appear to be running
Tor 0.2.5.10. dannenberg is running Tor 0.2.5.9-rc.

roger's dirauth (author of the post) moria1 (US) restarted ~1d ago and shows a
blip in traffic earlier today, which may or may not have something to do with
the post:
[https://atlas.torproject.org/#details/9695DFC35FFEB861329B9F...](https://atlas.torproject.org/#details/9695DFC35FFEB861329B9F1AB04C46397020CE31)

peter's tor26 (austria) restarted 12h ago:
[https://atlas.torproject.org/#details/847B1F850344D7876491A5...](https://atlas.torproject.org/#details/847B1F850344D7876491A54892F904934E4EB85D)

dizum (netherlands) was also recently restarted 16h ago:
[https://atlas.torproject.org/#details/7EA6EAD6FD83083C538F44...](https://atlas.torproject.org/#details/7EA6EAD6FD83083C538F44038BBFA077587DD755)

Tonga (netherlands) looks mostly normal, restarted ~7d ago:
[https://atlas.torproject.org/#details/4A0CCD2DDC7995083D73F5...](https://atlas.torproject.org/#details/4A0CCD2DDC7995083D73F5D667100C8A5831F16D)

sebastian's gabelmoo (germany) restarted 2d ago:
[https://atlas.torproject.org/#details/F2044413DAC2E02E3D6BCF...](https://atlas.torproject.org/#details/F2044413DAC2E02E3D6BCF4735A19BCA1DE97281)

CCC's dannenberg (germany) restarted 3d ago:
[https://atlas.torproject.org/#details/7BE683E65D48141321C5ED...](https://atlas.torproject.org/#details/7BE683E65D48141321C5ED92F075C55364AC7123)

jake's urras (US) is showing relatively low bandwidth & restarted ~2d ago:
[https://atlas.torproject.org/#details/0AD3FA884D18F89EEA2D89...](https://atlas.torproject.org/#details/0AD3FA884D18F89EEA2D89C019379E0E7FD94417)

Faravahar (US) restarted 4d ago:
[https://atlas.torproject.org/#details/CF6D0AAFB385BE71B8E111...](https://atlas.torproject.org/#details/CF6D0AAFB385BE71B8E111FC5CFF4B47923733BC)

riseup's longclaw (US) restarted 9d ago:
[https://atlas.torproject.org/#details/74A910646BCEEFBCD2E874...](https://atlas.torproject.org/#details/74A910646BCEEFBCD2E874FC1DC997430F968145)

linus's maatuska (sweden) has been up for 30d:
[https://atlas.torproject.org/#details/BD6A829255CB08E66FBE7D...](https://atlas.torproject.org/#details/BD6A829255CB08E66FBE7D3748363586E46B3810)

recent activity in tor's commit log may also offer up some clues:
[https://gitweb.torproject.org/tor.git/log/?showmsg=1](https://gitweb.torproject.org/tor.git/log/?showmsg=1)

~~~
geofft
How often do they tend to restart usually? (For instance, I'd be unsurprised
to hear e.g. that Roger tests his commits on his dirauth, and so that server
never has high service uptime, or something.)

~~~
justcommenting
i don't want to speak for roger, but my general understanding over the past
few years was that roger typically appeared to run fresher alpha code on a
sister relay named moriatoo
([https://atlas.torproject.org/#details/5C91CC4554CA2EE1904BA6...](https://atlas.torproject.org/#details/5C91CC4554CA2EE1904BA633A8B8AC8EB8C6B10B))
before upgrading moria1.

but at the moment, moriatoo is running 0.2.6.0-alpha-dev and moria1 is running
0.2.6.1-alpha-dev

------
driverdan
What are the specs of these servers and how much bandwidth do they require?

------
Aoyagi
>Tor remains safe to use.

What are these not-so-rare reports of mass unmasking of people then? I'm
genuinely curious, not begging the question.

~~~
cjbprime
These unmaskings have been performed through (usually egregious) opsec
failures on the part of the user, rather than performed by attacking the Tor
network directly.

~~~
bashinator
Also I believe there were some traffic correlation attacks where the attacker
was able to get netflow data from both entrance nodes and (?) the traffic
destination outside of Tor.

------
kordless
I'm hoping Utter.io can help with this by making the infrastructure more
trustworthy in the coming years. I'll be launching a Kickstarter right after
the 1st to raise money for the project (which is currently in preview mode):
[https://www.kickstarter.com/projects/kordless/683224456?toke...](https://www.kickstarter.com/projects/kordless/683224456?token=781b2ee9)

If funded, a user governed foundation will be set up to help prevent influence
by misaligned interests, such as those seen with existing providers and closed
source software vendors. Infrastructure was always meant to be open,
transparent and trustworthy.

Especially for those who don't know any better.

~~~
dsl
How old is this deck? AWS has 28 availability zones, and averages 4
datacenters per AZ. Way more than the 9 you claim...

~~~
kordless
First, I'd like to point out you are referring to something that isn't on the
Kickstarter page, but linked to by it. You are talking about this:
[http://utter.io/prezo](http://utter.io/prezo). Yes, it's a little out of
date. Yes, I substitute the industry's word 'datacenter' for Amazon's term
'region'.

Three days ago I updated the longer video version from that page and put it on
the Kickstarter page, down below the other video. In addition to removing
other content, I edited out the amounts you are referring to because they
change constantly and are less important to my pitch now I'm doing a
Kickstarter campaign. Also, AWS added a 10th region to their list a few months
ago. I don't 'count' the government cloud as a public offering.

It remains a truth that AWS runs out of ten geographic regions. So, 80% of the
world's public cloud is run out of (by your math) <~40 physical buildings. Not
a cloud, IMHO.

Besides, there doesn't appear to be any _public_ information on how many
physically different locations Amazon runs for AWS, which makes it impossible
to say how many physical locations (datacenters) they run. I'm not 100%
convinced that a 'zone' maps to a physical building, given my memory of ping
times across zones and having issues with two neighbor zones at the same time
in the early days of using AWS.

Amazon having different terminology than the industry's causes confusion and
my comments reflected that confusion when I used the term 'datacenter'
erroneously. FWIW, Rackspace calls their dataceneters 'datacenters':
[http://www.rackspace.com/about/datacenters](http://www.rackspace.com/about/datacenters).

Any remaining minutia related to this topic will be resolved by the end of the
week. I'm updating Utter.io in preperation for the Kickstarter launch.

