A judge has ordered that no more details about the attack should be provided to the defense in an affected Silk Road 2.0 case.
Update: Kenneth Walters, a spokesperson from CMU, told Motherboard in an email, "We have nothing to add beyond our Nov. 18 statement." When asked how the FBI knew that a Department of Defense research project on Tor was underway, so that the agency could then subpoena for information, Jillian Stickels, a spokesperson for the FBI, told Motherboard in a phone call that "For that specific question, I would ask them [Carnegie Mellon University]. If that information will be released at all, it will probably be released from them."
Update 25 Feb: In a statement, the Tor Project told Motherboard that "the Tor network is secure and has only rarely been compromised. The Software Engineering Institute ("SEI") of Carnegie Mellon University (CMU) compromised the network in early 2014 by operating relays and tampering with user traffic. That vulnerability, like all other vulnerabilities, was patched as soon as we learned about it. The Tor network remains the best way for users to protect their privacy and security when communicating online."
In November, Motherboard reported that a "university-based research institute" provided information to the Federal Bureau of Investigation that led to the identification of criminal suspects on the so-called dark web. Circumstantial evidence pointed to that body being the Software Engineering Institute (SEI) of Carnegie Mellon University (CMU). After a media-storm, CMU published a very carefully worded press release, implying that it had been subpoenaed for the IP addresses it obtained during its research.
Now, both the name of the university and the existence of a subpoena have been confirmed in a recent filing in one of the affected criminal cases.
"The record demonstrates that the defendant's IP address was identified by the Software Engineering Institute ("SEI") of Carnegie Mellon University (CMU") [sic] when SEI was conducting research on the Tor network which was funded by the Department of Defense ("DOD")," an order filed on Tuesday in the case of Brian Farrell reads. Farrell is charged with conspiracy to distribute cocaine, heroin, and methamphetamine due to his alleged role as a staff member of the Silk Road 2.0 dark web marketplace.
"Farrell's IP address was observed when SEI was operating its computers on the Tor network. This information was obtained by law enforcement pursuant to a subpoena served on SEI-CMU," the filing continues.
Between January and July 2014, a large number of malicious nodes operated on the Tor network, with the purpose, according to the Tor Project, of deanonymising dark web sites and their users. The attack relied on a set of vulnerabilities in the Tor software—which have since been patched—and according to one source, the technique could unmask new hidden services within two weeks.
This new court document shows that, as many suspected, SEI was indeed behind the attack on Tor.
Evidence has pointed to SEI being behind that attack: SEI researchers Alexander Volynkin and Michael McCord were due to present research at the Black Hat hacking conference in August 2014 on how to unmask the IP addresses of Tor hidden services and their users, before the talk was suddenly canceled without explanation. SEI also submitted a research paper to the 21st ACM Conference on Computer and Communications Security (CCS) in 2014 on unmasking dark web users and sites, although that paper was apparently based on simulations, rather than in-the-wild attacks. That research was funded by Department of Defense contract number FA8721-05-C-0003. (The Tor Project has made an unsubstantiated claim that CMU was paid by the FBI to the tune of at least $1 million to carry out the attack. The Tor Project did not respond to questions about this claim in light of the subpoena.)
This new court document shows that, as many suspected, SEI was indeed behind the attack on Tor, and that information obtained from that move was accessed by law enforcement via a subpoena, facts that Farrell's defense has been aware of for some time, judging by the latest filing.
When asked how the FBI knew that a Department of Defense research project on Tor was underway, so that the agency could then subpoena for information, Jillian Stickels, a spokesperson for the FBI, told Motherboard in a phone call that "For that specific question, I would ask them [Carnegie Mellon University]. If that information will be released at all, it will probably be released from them."
The Tor Project did not immediately respond to a request for comment, and neither did CMU, DoJ, or Farrell's representatives. This story will be updated if we hear back.
This latest order was in response to a motion to compel discovery filed by Farrell's defense in January. They have received "basic information" about the Tor attack, as well as the funding and structure relationship between SEI and DOD, according to the order, but have requested other materials too. The motion was denied by the Honorable Richard A. Jones.
Many of the filings are under seal, so it's not clear what exact information Farrell's lawyers have been trying to get hold of, but this latest order provides some indications. The defense has sought more information on the attack, and "disclosures regarding contacts between SEI, the Department of Justice, and federal law enforcement," the order reads, encompassing periods before and after SEI performed the attack itself, with a particular emphasis on meetings between the DoJ and SEI.
As for why the court ordered that no further details about how SEI operated and collected IP addresses should be provided to the defendant, Jones claimed that IP addresses, and even those of Tor users, are public, and that Tor users lack a reasonable expectation of privacy.
"SEI obtained the defendant's IP address while he was using the Tor network and SEI was operating nodes on that network, and not by any access to this computer," the order reads.
"In order for a prospective user to use the Tor network they must disclose information, including their IP addresses, to unknown individuals running Tor nodes, so that their communications can be directed towards their destinations. Under such a system, an individual would necessarily be disclosing his identifying information to complete strangers," the order continues.
This line of argument echoes that made in a recent case of FBI mass hacking, where a judge wrote that Tor doesn't give its users complete anonymity because users do have to provide their real IP address to a node of the network at some point. Indeed, in his order, Jones pointed explicitly to this ruling.
In sum, "SEI's identification of the defendant's IP address because of his use of the Tor network did not constitute a search subject to Fourth Amendment scrutiny," the order reads.
Jones adds that the request for further discovery was made "despite the understanding communicated by the Tor Project that the Tor network has vulnerabilities and that users might not remain anonymous." When it comes to the other requests made by Farrell's defense, the judge ordered they were irrelevant, overbroad, and that enough information has already been provided.
Farrell's case is far from the only one affected by SEI's attack on Tor.
Earlier this month, Gabriel Peterson-Siler pleaded guilty to one count of possession of child pornography, and another drug case in Ireland indicates it was also swept up in the institutes's actions. In fact, the search warrant issued against Farrell stated that approximately 78 IP addresses that accessed the vendor portion of Silk Road 2.0 were obtained. On top of this, the seizure of Silk Road 2.0 was part of the wider Operation Onymous, which ended in the shuttering of around 27 different dark web sites, suggesting that many more criminal suspects, or those already convicted, were likely discovered with the same approach.
The full court filing is embedded below.