Freedom Hosting, described by an FBI special agent as "the largest facilitator of child porn on the planet", has gone offline, as the FBI sought the extradition of a 28-year-old suspect from Ireland.
Eric Eoin Marques is the subject of a US arrest warrant for distributing and promoting child abuse material online.
He has been refused bail by the high court in Dublin, reported the Irish Independent, until the extradition request is decided. Marques, who is both a US and Irish national, will face the high court again on Thursday.
If extradited to the US, Marques faces four charges relating to images hosted on the Freedom Hosting network, including images of the torture and rape of children. He could be sentenced to 30 years in prison.
Freedom Hosting hosted sites on the The Onion Router (Tor) network, which anonymises and encrypts traffic, masking the identity of users.
Whistleblowers, journalists and dissidents too?
On Sunday, Tor's official blog posted a detailed statement confirming that a large number of "hidden service addresses", or servers anonymised using the network, had unexpectedly gone offline.
Tor was quick to distance itself from Freedom Hosting, which has been claimed to be a hub for child abuse material as well as Silk Road – the eBay of hard drugs, saying "the persons who run Freedom Hosting are in no way affiliated or connected to the Tor Project Inc, the organisation co-ordinating the development of the Tor software and research."
"Anyone can run hidden services, and many do," said the statement. "Organisations run hidden services to protect dissidents, activists, and protect the anonymity of users trying to find help for suicide prevention, domestic violence, and abuse recovery.
"Whistleblowers and journalists use hidden services to exchange information in a secure and anonymous way and publish critical information in a way that is not easily traced back to them. The New Yorker's Strongbox is one public example."
Security blogger and former Washington Post reporter Brian Krebs wrote on Sunday that users were identified using a flaw in Firefox 17, on which the Tor browser is based.
Rik Ferguson, vice-president of security research at Trend Micro, said he was awaiting further details to be made public as Marques is brought to trial, but that the takedown and related law enforcement "is great news for the campaign against child exploitation".
"The malicious code made a 'victim machine' which visited one of the compromised hidden sites, and requested a website on the 'visible' web, via HTTP, thereby exposing its real IP address. As the exploit did not deliver any malicious code, it is highly unlikely that this was a cybercriminal operation.
"It is a legitimate concern that users of child abuse material may simply go elsewhere, and as such the individual users should continue to be targeted by law enforcement globally. However, going after the people and organisations that really enable this content to be made available at all is a much more effective strategy."
In 2011, hacking collective Anonymous took down Freedom Hosting with a targeted DDos attack as part of an anti-paedophile campaign. Anonymous also published details of the accounts of 1,500 members of Lolita City, claiming Freedom Hosting was home to 100GB of child abuse material.
FBI conspiracy?
Users on the Tor sub-Reddit were suspicious about the news, dissecting the details of the vulnerability and pointing to a previous case where the FBI had taken over and maintained a site hosting child abuse material for two weeks in order to identify users.
"FBI uploads malicious code on the deep web sites while everyone is off at Defcon. Talk about paying dirty," commented VarthDaTor. Defcon is an annual event in the US for security experts and hackers.
"The situation is serious," said gmerni. "They got the owner of FH and now they're going after all of us. Half the onion sites were hosted on FH! Disable Javascript in your Tor browser for the sake of your own safety."
This article originally appeared on guardian.co.uk
