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Attacking Tor: How the NSA targets users' online anonymity

theguardian.com

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Re: Attacking Tor: How the NSA targets users' online anonymity

#41

Post by elwin »

tptacek wrote: post #39
elwin wrote: post #29

Earlier quoted context omitted.

Attacking Tor by passive analysis is one thing. Installing spyware, creating a botnet, and making the infection process quick and easy is another. There might be some justification for the former. The latter is too risky.

It's not a "Manhattan Project" if it's within the capabilities of any decent-sized organized crime syndicate. People here have short memories. In the 1990s, teenaged hackers owned up the backbone.

I called them analogous because of their potential effects and their development in secret by governments. I don't think a crime syndicate could do it so effectively; when the NSA "owns up the backbone", even if the operator discovers the intrusion, it stays owned.

Re: Attacking Tor: How the NSA targets users' online anonymity

#42

Post by pyre »

kilroy123 wrote: post #25

Sounds like, if you're going to do something very sensitive on tor, you need to: - always have an update to date version of tor bundle! - compile the bundle yourself from source - run it virtually, and always roll back to a clean snapshot (before installing it tor) when done - if possible use from a network that is not your own (open wifi, public wifi, etc.) - spoof your mac address - do not run JS, Java applets, etc…

It's probably the best you can do, but it still doesn't prevent your anonymity from being compromised. As soon as the malware is installed, it can phone home, even if you end up wiping it after you are done.

Re: Attacking Tor: How the NSA targets users' online anonymity

#43

Post by shabble »

bryze wrote: post #35
kilroy123 wrote: post #25

Sounds like, if you're going to do something very sensitive on tor, you need to: - always have an update to date version of tor bundle! - compile the bundle yourself from source - run it virtually, and always roll back to a clean snapshot (before installing it tor) when done - if possible use from a network that is not your own (open wifi, public wifi, etc.) - spoof your mac address - do not run JS, Java applets, etc…

Yeah, I was wondering if a virtual machine is safe from malicious attacks, though. Can anyone comment on the feasibility of this method as fail-safe?

Ideally you'd want to be running Tor with transparent proxying of all traffic on a physically separate (and locked down) host. I believe there are guides on how to do all that on a raspberry pi out there.

On your primary browsing/whatever machine, I believe (but have not exhaustively researched) that it would still make sense to run inside a VM/container, because that would provide a much more 'generic' set of system characteristics (MAC address, clock jitter stats, CPUinfo, etc) than your actual hardware. It does provide a greater attack surface, so you'd have to weigh up the value of potentially masking physical identity vs likelihood of gaining root due to VM exploits.

There's also the risk of overconfidence because of these measures, which might lead you to overlook important details in the host OS, or in your communication habits.

Re: Attacking Tor: How the NSA targets users' online anonymity

#44

Post by tedks »

tptacek wrote: post #7

Metacommentary: I've taken a jaundiced view of "liberation tech" efforts in the past and this is as good an illustration as any of why. Among "amateur" libtech projects, Tor is about as good as you get --- an active community, extremely widespread use, technical people with their heads screwed on right and as much humility as you can reasonably expect of people whose projects are (candidly) intended to thwart world g…

>(here, there's a subtext that Tor actually made NSA's job easier)

I'm not sure how you reached that conclusion.

The slides mention that Tor is:

* Very difficult to identify on the network-level, since Tor-tls traffic is indistinguishable from Apache-tls traffic as of 2011

* Impossible to fully deanonymize

* Only exploitable via a handful of browser exploits.

Further, later in the "Tor is the King" slide deck, there's this rather glowing endorsement of the TAILS livecd:

"Tails... adds severe misery to CNE equation."

...which is what you'd expect, given that TAILS is entirely ephemeral, and so all of their callbacks and APT-style attacks are useless against it.

I had previously considered TAILS a rather "amateur" system myself, because of the glut of livecds bundling Tor. But it turns out they're actually adding severe(!) misery to the NSA's exploitation team! I'm downloading the TAILS cd now so I can switch over to using it in a VM rather than running Tor Browser Bundle on my own machine.

Re: Attacking Tor: How the NSA targets users' online anonymity

#45

Post by makmanalp »

tptacek wrote: post #7

Metacommentary: I've taken a jaundiced view of "liberation tech" efforts in the past and this is as good an illustration as any of why. Among "amateur" libtech projects, Tor is about as good as you get --- an active community, extremely widespread use, technical people with their heads screwed on right and as much humility as you can reasonably expect of people whose projects are (candidly) intended to thwart world g…

Speaking of which, now is probably a great time to mention that the Berkman Center is doing an open call for fellowship applications:

http://cyber.law.harvard.edu/getinvolved/fellowships

And I'm sure the EFF is looking too.

Re: Attacking Tor: How the NSA targets users' online anonymity

#46

Post by aestra »

tptacek wrote: post #7

Metacommentary: I've taken a jaundiced view of "liberation tech" efforts in the past and this is as good an illustration as any of why. Among "amateur" libtech projects, Tor is about as good as you get --- an active community, extremely widespread use, technical people with their heads screwed on right and as much humility as you can reasonably expect of people whose projects are (candidly) intended to thwart world g…

I wouldn't really consider Tor an amateur libtech product since the basics of the underlying technology (onion routing) was developed by the US Navy.

Here's the original patent from 1998:

http://patft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=...

Re: Attacking Tor: How the NSA targets users' online anonymity

#47

Post by sitkack »

pyre wrote: post #42
kilroy123 wrote: post #25

Sounds like, if you're going to do something very sensitive on tor, you need to: - always have an update to date version of tor bundle! - compile the bundle yourself from source - run it virtually, and always roll back to a clean snapshot (before installing it tor) when done - if possible use from a network that is not your own (open wifi, public wifi, etc.) - spoof your mac address - do not run JS, Java applets, etc…

It's probably the best you can do, but it still doesn't prevent your anonymity from being compromised. As soon as the malware is installed, it can phone home, even if you end up wiping it after you are done.

The malware would have to escape the virtual machine. The VM needs to be firewalled off from the host and NOT have the host guest tools installed.

Re: Attacking Tor: How the NSA targets users' online anonymity

#48

Post by chakalakasp »

kilroy123 wrote: post #25

Sounds like, if you're going to do something very sensitive on tor, you need to: - always have an update to date version of tor bundle! - compile the bundle yourself from source - run it virtually, and always roll back to a clean snapshot (before installing it tor) when done - if possible use from a network that is not your own (open wifi, public wifi, etc.) - spoof your mac address - do not run JS, Java applets, etc…

If you are doing something that would make the NSA interested in you (and I would highly highly discourage that), you'd need to focus more on tradecraft. Get the laptop from a source that can't be traced to you, like a thrift store in a city where you don't live or normally frequent. Disguise yourself, pay in cash, and either make sure there are no security cameras or wait a good year before you do whatever you are going to do (nobody keeps camera data longer than that). When you do whatever you are doing, use a Live CD like tails. Disguise yourself. Wear gloves. Go to a city you don't live in or frequent regularly, and only use cash during the trip. Park a long distance from your wifi source where there are no cameras and walk to where you will access the wifi. Use a cantenna to hit an open wifi some distance away, preferably a public connection like a busy coffee shop. Do whatever you are going to do. Walk back to your car, drive to a nearby town, smash the laptop and dispose of in a dumpster. Drive home.

Re: Attacking Tor: How the NSA targets users' online anonymity

#49

Post by pitchups »

It appears that the NSA has been able to target only Tor users that are using the Tor - Firefox bundle. So if you are using Chrome or some other browser - configured to use Tor, you would be safe from these exploits. Wouldn't most sophisticated hackers - or other high value targets most likely to be of interest to the NSA - be already doing that, rather than using the Firefox+Tor bundle?

Re: Attacking Tor: How the NSA targets users' online anonymity

#50

Post by sitkack »

bryze wrote: post #35
kilroy123 wrote: post #25

Sounds like, if you're going to do something very sensitive on tor, you need to: - always have an update to date version of tor bundle! - compile the bundle yourself from source - run it virtually, and always roll back to a clean snapshot (before installing it tor) when done - if possible use from a network that is not your own (open wifi, public wifi, etc.) - spoof your mac address - do not run JS, Java applets, etc…

Yeah, I was wondering if a virtual machine is safe from malicious attacks, though. Can anyone comment on the feasibility of this method as fail-safe?

There are plenty of ways to breakout of a VM. What if the VM has a filesystem that is readonly by the host?

Drive by download, cookie fs drop, etc. Attack the indexing server, file previews, etc.

You really want to run the VM on an external host like a raspberry pi and the VM should different than the host running Tor.

Tor should really be rewritten in a Coq proven Haskell program.

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