4 ms·

It's been known from the beginning Tor's design can't defend against these sorts of attacks.

by htns 11y ago

twblalock 11y ago
If it has always been known, then why is it making so much news? Tor's purpose is to anonymize traffic. What is it good for, if it can't do that?
- georgerobinson 11y ago
  Tor can anonymize traffic but only against passive attackers who cannot perform traffic flow confirmation on a global scale. > A global passive adversary is the most commonly assumed threat when analyzing theoretical anonymity designs. But like all practical low-latency systems, Tor does not protect against such a strong adversary. Instead, we assume an adversary who can observe some fraction of network traffic; who can generate, modify, delete, or delay traffic; who can operate onion routers of his own; and who can compromise some fraction of the onion routers. (https://svn.torproject.org/svn/projects/design-paper/tor-design.pdf https://svn.torproject.org/svn/projects/design-paper/tor-des..., Page 4) I read an interesting article in the ACM last month, titled "Seeking Anonymity in an Internet Panopticon" (http://cacm.acm.org/magazines/2015/10/192387-seeking-anonymity-in-an-internet-panopticon/fulltext http://cacm.acm.org/magazines/2015/10/192387-seeking-anonymi...). > The most well known global-traffic-analysis attack—"traffic confirmation"—was understood by Tor's designers but considered an unrealistically strong attack model and too costly to defend against. They explain a number of attacks against Tor (both active and passive) and introduce Dissent, "a project at Yale University that expands the design space and explores starkly contrasting foundations for anonymous communication".
  - ENOTTY 11y ago
    Isn't that the exact threat model that the CERT researchers followed? The Tor Project found only 115 relays (6.4%) in the network that was emitting the signal. That's not the aforementioned Globally Passive Adversary. So by their own measurement the Tor project failed. That said, they took steps to mitigate the exact vulnerability these researchers exploited.
snowwrestler 11y ago
I'm not unfamiliar with Tor, and I would not be surprised to hear that the NSA, with all their resources, was able to pierce its anonymity. I am very surprised that a couple of guys at a university could do so. That's definitely within the realm of attacks that Tor was supposed to be secure against.

It's been known from the beginning Tor's design can't defend against these sorts of attacks.

by htns 11y ago

It's been known from the beginning Tor's design can't defend against these sorts of attacks.

If it has always been known, then why is it making so much news? Tor's purpose is to anonymize traffic. What is it good for, if it can't do that?

georgerobinson 11y ago
Tor can anonymize traffic but only against passive attackers who cannot perform traffic flow confirmation on a global scale. > A global passive adversary is the most commonly assumed threat when analyzing theoretical anonymity designs. But like all practical low-latency systems, Tor does not protect against such a strong adversary. Instead, we assume an adversary who can observe some fraction of network traffic; who can generate, modify, delete, or delay traffic; who can operate onion routers of his own; and who can compromise some fraction of the onion routers. (https://svn.torproject.org/svn/projects/design-paper/tor-design.pdf https://svn.torproject.org/svn/projects/design-paper/tor-des..., Page 4) I read an interesting article in the ACM last month, titled "Seeking Anonymity in an Internet Panopticon" (http://cacm.acm.org/magazines/2015/10/192387-seeking-anonymity-in-an-internet-panopticon/fulltext http://cacm.acm.org/magazines/2015/10/192387-seeking-anonymi...). > The most well known global-traffic-analysis attack—"traffic confirmation"—was understood by Tor's designers but considered an unrealistically strong attack model and too costly to defend against. They explain a number of attacks against Tor (both active and passive) and introduce Dissent, "a project at Yale University that expands the design space and explores starkly contrasting foundations for anonymous communication".
- ENOTTY 11y ago
  Isn't that the exact threat model that the CERT researchers followed? The Tor Project found only 115 relays (6.4%) in the network that was emitting the signal. That's not the aforementioned Globally Passive Adversary. So by their own measurement the Tor project failed. That said, they took steps to mitigate the exact vulnerability these researchers exploited.

snowwrestler 11y ago

I'm not unfamiliar with Tor, and I would not be surprised to hear that the NSA, with all their resources, was able to pierce its anonymity. I am very surprised that a couple of guys at a university could do so. That's definitely within the realm of attacks that Tor was supposed to be secure against.