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Around 20 per cent of all websites on the dark web were taken offline in a hack, with those responsible publishing details of the website administrators.

Freedom Hosting II, a site with 10,000 Tor-based webpages, was attacked after a hacker said child pornography was being hosted on the websites.

On Friday, visitors to any of the websites hosted by the firm saw the message: "Hello, Freedom Hosting II, you have been hacked." The statement explained that when the attacker was searching through Freedom Hosting II's database, they found 50 per cent of websites were "child porn" noting, "you host many scam sites".

The hack has been confirmed by security experts and a list of impacted websites was curated and posted online.

The attacker, who told Motherboard it was their first ever hack, also claimed to take 74GB of files and a 2.3GB database.

Since the breach, the Freedom Hosting II database has been made available on information sharing websites and been verified. Troy Hunt, whose Have I Been Pwned website holds more than two billion compromised online accounts, has been given the 2GB MySQL database and says it includes 381,000 email addresses.

Describing the data breach Hunt said it is a "pretty serious incident" and the database has backups from customers, including those running WordPress websites with the dark web host. "As you can imagine, a lot of the data is very explicit," he says.

Within the email addresses, Hunt says there are "thousands" of .gov addresses but cautions they may not be legitimate.

While the dark web is known to host child pornography and allow the sales of drugs and illegal services, it is also used by journalists and those wishing to avoid surveillance from oppressive regimes. It is likely the database of leaked email addresses affects those who use the anonymous browsing method for legal purposes.

Dark web and privacy researcher Sarah Jamie Lewis conducted a review of Freedom Hosting II in October 2016 and said she believed there were 1,500 to 2,000 active sites being hosted.

"FHII made it easy for people to start playing with anonymous publishing - and in doing so created a huge vulnerability," Lewis tweeted. "I have never been a fan of dark web hosting providers. The threat model there for everyone is ridiculously hard to secure."

Hunt also said the details included on the Freedom Hosting II are likely to have been collected by police and intelligence agencies. "Law enforcement will absolutely have this data, it's *very* public. It also obviously has many real email addresses in it".

See more here:

Hackers took more than 10000 dark web sites offline - Wired.co.uk