[tor-relays] [Important] Update on an upcoming German broadcasting story about Tor/Onion Services

[isabela fernandes]

Hi Tor,

I am reaching out to inform you of an upcoming news story concerning a
potential deanonymization attack on Onion Services.

What is happening?

On September 9, 2024, The Tor Project received a press inquiry from
Norddeutscher Rundfunk (NDR, part of ARD, a German public broadcaster) with
a request for comment to their upcoming reporting of "investigative
measures by German and international law enforcement agencies in the Tor
network, in particular the localisation and deanonymisation of onion
services." We complied with the outlet's deadline of September 12th and
answered a series of questions.

The reporter claims to have "evidence that shows that in several cases
German law enforcement authorities were able to locate the Tor entry node
of onion services and thus successfully deanonymise Tor users. V2 and V3
onion addresses were affected at least between Q3/2019 and Q2/2021." The
reporter further claims that "law enforcement agencies used so-called
timing analyses and broad and long-term monitoring of Tor nodes in data
centres."

As of today, The Tor Project has not been granted access to supporting
documents, and has not been able to independently verify if this claim is
true, if the attack took place, how it was carried out, and who was
involved.

In the absence of facts, it is hard for us to issue any official guidance
or responsible disclosures to the Tor community, relay operators, and users
at this time.

We are calling for more information from you.

If you have any information that can help us learn more about this alleged
attack, please email security at torproject.org.

If you want to encrypt your mail, you can get the OpenPGP public key for
this address from keys.openpgp.org. Fingerprint: 835B 4E04 F6F7 4211 04C4
751A 3EF9 EF99 6604 DE41

Your assistance will help all of us take the necessary steps and
precautions to keep Onion Services safe for the millions of users that rely
on the protections Tor provides.

Are Tor users safe?

Tor users can continue to use Tor Browser to access the web securely and
anonymously. Nothing that the Tor Project has learned about this incident
suggests that Tor Browser was attacked or exploited. We encourage Tor
Browser users and relay operators to keep software versions up to date.

The reporter's questions focus on the use of onion services and .onion
addresses. Which leads us to assume that the alleged attack was targeting a
specific .onion site.


We will continue to share updates on this email as this situation evolves.

Thank you!

Isabela
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