The new site is a mirror of existing material.
ISIS now has a dark web site. A mirror of an ISIS propaganda site has launched as a Tor hidden service, likely in an attempt to make its material more resilient to take-downs, or to protect the identity of the group's supporters.
Online terrorism researcher Scot Terban wrote on his blog on Sunday that the Al-Hayat Media Center, which is affiliated with ISIS, "has posted a link and explanation on how to get to their new dark net site" on a forum associated with the group.
Links to the site were also published by a number of jihadi-linked Twitter accounts, Motherboard found.
"It's legitimate," J M Berger, co-author of the book ISIS: The State of Terror, told Motherboard in an email. "My understanding is that this is just a mirror" of another ISIS site, he added. This means that the site is only republishing content from elsewhere. Mirrors are often used when sites are at risk of being taken down.
The normal clear [web] site is offline, it's been up and down on different domains for some months
The site contains an archive of existing ISIS materials, including everything from the group's call for jihadis to attack Balkan countries, to its documentary-style film The Flames of War.
Generally, there are two obvious benefits to using a Tor hidden service. First of all, a visitor typically has to use Tor in order to access it, which masks their IP address and protects their identity.
The second benefit is that, if configured correctly, the servers running the website will also enjoy the anonymity protections rewarded by Tor, so law enforcement will have a harder time tracking them down.
But some jihadi Twitter accounts are giving out shoddy security advice for accessing the site by providing the link with a ".onion.link" suffix rather than the normal ".onion," which lets users access the site without routing their traffic through the Tor network.
That's not the only security worry. Although the site is running as a Tor hidden service, it appears that at least some of the video content is still hosted elsewhere on the surface web, meaning the visitor is ultimately directed away from the dark web anyway.
Regardless, putting this propaganda on the dark web means it might stay up for longer than its clear web counterpart. "The normal clear [web] site is offline, it's been up and down on different domains for some months," Berger noted.
Islamic terrorists have had their own bulletin boards and propaganda sites for decades. Al Qaeda's first official site was launched way back in 2001. Plenty of other forums have come and gone since then, many of them suffering periods of down time.
Commentators have already blamed the increased use of encryption for being a barrier stopping law enforcement from anticipating last week's Paris attacks. This new site is likely to stoke the fires of the debate around privacy-enhancing tools and security further.