Agora, one of the largest online black market sites, halted operations after concerns arose that vulnerabilities in Tor's hidden services could lead to its servers being located.
The concerns stem from a Massachusetts Institute of Technology (MIT) study, released last month, detailing how certain attacks could expose servers, according to published Reports.
“We have recently been discovering suspicious activity around our servers which led us to believe that some of the attacks described in the research could be going on,” Agora's administrators said in a message originally posted to Agora's dark web home and then reposted to Reddit.
Administrators said they are moving their servers and would remain offline until all problems are mitigated. The statement also said that they would do their best to clear all outstanding orders and recommended that all users withdraw money from their accounts.
A Tor Project spokesperson told SCMagazine.com via email correspondence Thursday that they are not in communication with Agora and so are unsure of their reasoning.
“There are known theoretical and research attacks against hidden services, but little demonstration of their value in practice, and the entire area needs more research and development,” the spokesperson said.
Tor Project added, "that none of the known attacks against the hidden services apply to Tor Browser users."