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Re:Deanonymizing Tor Circuits by Santosh83 on Sunday February 02, 2020 @04:30AM (#22216067)
Which the larger countries do. And the main point of Tor is to evade serious adversaries isn't it? If you're not anonymous from nation states when using Tor, then what will protect whistle-blowers and investigative journalists and dissidents? VPNs can be ordered to turn over data by courts and you can never be sure a "no logs" VPN does what it says. Tor is the only viable alternative and we know it can be at least seriously compromised by the bigger nations.
Re:Deanonymizing Tor Circuits by euro_expat on Sunday February 02, 2020 @08:02AM (#22216732)
Tor however has always made the disclaimer that even basic correlation attacks will defeat its anonymity. People use it as the de facto tool for beating the big guys, but it provides no such capability or claim of such. This seems to not be so well known though.
Re:Deanonymizing Tor Circuits by belorn on Sunday February 02, 2020 @10:38AM (#22217354)
The only thing that can work against big national agencies is security in depth, in which tor can be part. Tor is also better than nothing, which is a better de factor tool than plain text.

In modern society everything gather meta data. The phone, the credit card, the mass transit system, cameras with face recognition, the isp, all the routers between A and B, the devices people own, the platforms they socialize on. Its almost impossible to make a face to face meeting without allowing nation agencies to know about it. A leaker wanting to talk to a journalist without risking becoming a target might not be 100% protected by tor, but then I don't know any single better method right now. Some combination of obfuscation, encryption, mixing, and plausible deniability seems to be the best bet.

Re:Deanonymizing Tor Circuits by Astarte on Sunday February 02, 2020 @11:35AM (#22217740)
>Some combination of obfuscation, encryption, mixing, and plausible deniability seems to be the best bet.

Go on.

Re:Deanonymizing Tor Circuits by belorn on Sunday February 02, 2020 @02:03PM (#22218638)
Ie, talk in code, use VPN, use shared communication streams like Tor, and make your behavior look legit and boring. Of course I am not speaking as a professional opsec specialist agent.

As far as you know.

Re:Deanonymizing Tor Circuits by DyslexicAtheist on Sunday February 02, 2020 @08:54AM (#22216902)
not making such claims is a the only way to be taken seriously by the community it serves. Those using tor-browser know it's a best effort approach.

The same attitude should be expected from all InfoSek vendors. But it's easier to sell a product with claims it will protect you rather than saying the truth (that it's riddled with edge-cases like everything else).

Tor, unlike many of the VPN companies, thankfully lack a marketing department trying to push it with incorrect claims about its alleged ability.

edit: if the threat model is to protect against corporate mass-surveillance ("the big guys"), then Tor is incredibly effective. They wouldn't go through the trouble to identify and blacklist exit nodes and present users with a captcha otherwise. (ofc assuming that it is used correctly: never log in, or if you must only log-in with sock-puppet identities etc).

Re:Deanonymizing Tor Circuits by Astarte on Sunday February 02, 2020 @09:55AM (#22217168)
>They wouldn't go through the trouble to identify and blacklist exit nodes and present users with a captcha otherwise.

Do you really think they care about that 1% (made up number) of Tor users using their service legitimately? Or do they just want to avoid being attacked or their service being abused?

Re:Deanonymizing Tor Circuits by tutfbhuf on Sunday February 02, 2020 @05:34AM (#22216280)
Has there been any known case where a person using Tor has been tracked down and put into curt, without human mistake that lead to his de-anonymization?
Re:Deanonymizing Tor Circuits by mirimir on Sunday February 02, 2020 @06:30AM (#22216466)
Yes. See https://news.ycombinator.com/item?id=22215126

Not one person. Hundreds, maybe thousands. Because of a exploited vulnerability, and failure to pay attention to an upsurge in suspicious relays.

Unless you consider that the mistake was using Tor directly, rather than through a VPN service.

Re:Deanonymizing Tor Circuits by belorn on Sunday February 02, 2020 @08:05AM (#22216737)
https://blog.torproject.org/tor-security-advisory-relay-earl...

A bit more detail would be welcome about those "Hundreds, maybe thousands" of persons. Clearly the security researcher did find a vulnerability in the protocol and confirmed it by unmasking users, but I don't see the support for people getting "tracked down and put into [court]".

More important, what purpose is there to reference a 5 year old patched security vulnearbility? The same year as the above vulnerability was found in Tor, HTTPS was also broken with Heartbleed. The only fool-proof security is security in so many layers that it become statistically unlikely to cause a negative impact.

Re:Deanonymizing Tor Circuits by mirimir on Sunday February 02, 2020 @08:39AM (#22216848)
The issue isn't that the CMU people exploited the "relay early" bug. It's that the FBI subpoenaed all their data, tracked down onion services, and served malware.

This is just the outcome from busting one site, PlayPen:

    At least 350 U.S.-based individuals arrested
    25 producers of child pornography prosecuted
    51 hands-on abusers prosecuted
    55 American children successfully identified or rescued
    548 international arrests, with 296 sexually abused children identified or rescued
https://www.fbi.gov/news/stories/playpen-creator-sentenced-t...
Re:Deanonymizing Tor Circuits by belorn on Sunday February 02, 2020 @10:21AM (#22217282)
While that linked article does not directly talk about relay early, this article does: https://blog.torproject.org/did-fbi-pay-university-attack-to...

The article says that they likely did not have a warrant and simply just went and hired the researcher directly.

But fair enough, the claim that hundreds did get tracked down and arrested, due to a bug found by a security researcher after getting hired by the FBI, is true.

People selling zero days vulnerabilities is a major problem to security. Sadly it is something which new threat models need to take into consideration. The Tor Project did change how the Tor browser bundle updates, and I suspect this event did also caused some ripples in the project in how much they can trust researchers.

Re:Deanonymizing Tor Circuits by Astarte on Sunday February 02, 2020 @08:42AM (#22216864)
It depends on who runs these attacks. Some law enforcement agency could use those attacks to put you in jail. Mapping out Tor users can be interesting to other entities, too ... As you can see from the original article these attacks happen. They are also run against more interesting websites or individuals. Obviously, the attackers won't write a publication for their vulnerabilities ;) Related: https://medium.com/@nusenu/the-growing-problem-of-malicious-...

Once in while, Tor node operators will complain about DDOS on the tor mailing lists or similar sites. In most of the cases this is just an attempt to figure out guard nodes or real IP addresses of an individual or server.

Re:Deanonymizing Tor Circuits by mirimir on Sunday February 02, 2020 @10:00PM (#22221077)
Oops, I neglected to address this point:

> More important, what purpose is there to reference a 5 year old patched security vulnearbility?

Sure, it's old, and everyone screws up sometimes.

A few things bother me about it. One is that we know that the Tor Project did notice the malicious relays that CMU people were hosting. From what I've read, they weren't subtle about it.

So basically Tor Project staff said that they screwed up, and apologized. But somehow that just doesn't feel plausible.

There's also some email obtained through FoIA which could be read as evidence that "Tor developers are closely working with the US government".[0]

Sure, maybe that's just paranoia and conspiracy theory. And I do appreciate the delicacy of supporting strong anonymity for Tor without defending child pornographers.

0) https://restoreprivacy.com/tor/

Re:Deanonymizing Tor Circuits by jlgaddis on Sunday February 02, 2020 @12:53PM (#22218207)
(I don't have a link handy and I'm going from memory here so I apologize if I've screwed anything up...)

There was a Harvard student a few years ago who got busted for e-mailing a bomb threat (during finals, maybe?) or something like that.

The school reviewed their (Netflow?) logs, found the users on their network who were using Tor at the time and so he quickly became a suspect (and confessed when questioned, IIRC).

If he hadn't been on the school's network, it would have obviously been much more difficult, if not impossible, to find him so I suppose this one could be classified as an opsec fail.

Re:Deanonymizing Tor Circuits by 4gotunameagain on Sunday February 02, 2020 @05:43AM (#22216313)
I would imagine that if anyone had this capability, they would go into great extents to hide it's existence.
Re:Deanonymizing Tor Circuits by azalemeth on Sunday February 02, 2020 @05:12AM (#22216205)
What about i2p and Freenet?
Re:Deanonymizing Tor Circuits by mirimir on Sunday February 02, 2020 @06:57AM (#22216544)
About Freenet, see https://news.ycombinator.com/item?id=22216177

I2P was rather like the love child of Freenet and Tor. Like Freenet, it's pure P2P, where all users route traffic for each other. And although there are outproxies to the open Internet, it's mostly about I2P-hosted content. If anything, it's mostly like Tor onion services.

It uses a version of Tor's onion routing, called garlic routing. The main difference is that I2P tunnels are unidirectional, whereas Tor tunnels are bidirectional. That will allow for content caching and bundling, but that's not implemented yet.

There are reportedly ~10^4 I2P nodes, versus ~2x10^6 Tor users and ~6x10^3 relays. It's been argued that unidirectional tunnels are harder to deanonymize than bidirectional tunnels. But on the other hand, all I2P nodes are readily discoverable by malicious peers, but Tor users are much harder to discover, because Tor clients don't change guards frequently.

So bottom line, they arguably provide similar anonymity.

Edit: Yes, guards can discover users. But Tor is designed to make it hard for a given guard to see that many users. So you'd need lots of guards. And that's not so easy, because Tor folk are constantly on the lookout for suspicious guards, especially when a bunch show up at the same time.

Re:Deanonymizing Tor Circuits by Astarte on Sunday February 02, 2020 @08:26AM (#22216812)
> but Tor users are much harder to discover, because Tor clients don't change guards frequently.

I don't get that. Every guard can discover users because the users directly connect to guard nodes. As a guard you can just collect the real IP addresses of Tor users except they use a VPN or proxy to connect to the Tor network.

Re:Deanonymizing Tor Circuits by Astarte on Sunday February 02, 2020 @12:49PM (#22218178)
>So you'd need lots of guards

Can't edit my other reply. The operator in the OP runs 68 nodes. I did not look at each one, but it looks like most, if not all of them are guard nodes. This article mentions someone running at least 10% of the guard capacity: https://medium.com/@nusenu/the-growing-problem-of-malicious-... Tor's design obviously failed. Everyone can become a guard. You just need some patience. Also other nodes like DirAuths, bridges, fallback directories can discover Tor users.

Re:Deanonymizing Tor Circuits by mirimir on Sunday February 02, 2020 @07:25PM (#22220464)
Yes, that is an issue for Tor. But it's still arguably worse for I2P, because all peers can connect to each other.

But regardless, that's why I never use Tor or I2P from home, except through nested VPN chains. I don't care so much about VPS, because I'm very careful to isolate myself from them. For dedicated servers, however, which are more expensive, and where I invest more work for setup, I also use nested VPN chains.