On the first day of Christmas my true love sent to me an index of the dark web for free…..

The cybercriminal underground has once again served up a festive treat for the holiday season in the form of a smart dark web indexing service called QUO. 

QUO has slowly been gathering a reputation as a one-stop shop serving all of the cybercriminal community’s needs. I know what you’re thinking at this point…. “Oh no, not another dark web index!” Well, you’d be right—there is a whole host of similar services out there. But QUO wants to be the Christmas catalog that every dark web user will be leafing through to find ideas for their Christmas “treats” this year.

In a way—and bear with me on this one!—QUO’s goals are not too dissimilar to those of Santa’s workshop. Yes, the two services have entirely different customer bases. But both must meet all different kinds of requirements, filtering out the good requests from the bad. I sense you’re not yet convinced of this analogy… So this blog will break down QUO’s components and demonstrate why it may be more similar to Mr Claus’s toy factory than you might think.

What is QUO?

QUO describes itself as “a dark web, full-text search engine designed to create a continuously updated index of onion pages.” QUO allows its users to “explore the dark web quickly and anonymously, without logs, cookies, and JavaScript.”

QUO’s “About” page lists its many features and abilities, including:

  • “Get relevant results instantly
  • Millions crawled pages across 20k onion sites
  • Search all sites, or a specific site using the “site:” prefix
  • New onion sites added automatically
  • Mirror pages automatically grouped to avoid SPAMMY results
  • Non-functional or offline sites removed automatically
  • Sites with CP content blacklisted automatically (by AI)
  • Reported sites checked for relevancy (by AI)
  • No logs, no Cookies, no JavaScript
  • Robots.txt supported”

At the time of writing, QUO’s index contains over 200GB of data about approximately 8 million pages from around 20,000 thousand sites, including URL, title, metadata, keywords, and headings.

While Santa has his team of elves to help him bring his service to life, QUO has a team of sponsors, including several dark web marketplaces (DarkTor, Empire Market, and Imperial Market), a Bitcoin mixing service (BitMix.biz), and an illegal gift card generating service (GiftHub).

Figure 1: A list of QUO’s sponsors

What has QUO got to do with Christmas?

The List

Everyone knows that Santa has a list containing the name of every child in the world along with the Christmas gifts they’d like that year. QUO has a list of its own in the form of a database containing a constantly-updated list of Onion domains. Just as Santa marks each child’s name to show whether they have been naughty or nice in a given year, QUO flags each Onion domain as “Online”, “Offline”, or “Blacklisted”.

The Reporter

To make sure Santa’s list is up to date, parents work with Santa to let him know when their child has misbehaved so that the list can be updated accordingly. QUO has a similar function that enables its users to report Onion domains containing inappropriate content that may have slipped through QUO’s vetting process and inadvertently made their way onto the list. 

The Crawler

Once the list is finalized, the process of manufacturing begins. Whether it be toys or domains, each item has to be processed one by one. Without an elf to oversee the process and ensure all toys are built to the correct specifications, millions of children would wake up to a disappointing, substandard present on Christmas morning. 

QUO’s supervisory elf takes the form of a crawler that uses a spider to ensure all pages associated with a domain are seen and added to the index. Just as the elf highlights when a toy is faulty and adds it to the queue for reprocessing, the spider picks up any new URLs on the pages associated with a given domain and adds them to the list for processing at a later date.

The Mirror

With so many different toys to make and so many different children to account for, chances of duplication are high. Santa’s elves need a robust organizational system to make sure that two elves aren’t working on the same toy for the same child at the same time. 

There is also a very high probability of duplication on the dark web, especially with the number of different mirror domains for the same site. If they are not appropriately filtered out, it could cause havoc with the platform’s index. So QUO’s mirror engine goes through all of the index’s pages to identify duplicate sites. Rather than simply discarding these URLs, the engine will group these sites together and add them to the mirror options list of any given domain.

The Sweep

Santa’s workshop is a major operation. And just like any large-scale manufacturing process, there is the odd chance of mistakes—in this case, a toy being built for a child on the naughty list. To mitigate this risk, an elf manager might check all of the finished toys to ensure all the packages in Santa’s sack are correctly labelled up for the good children and replace any gifts mistakenly wrapped up for the naughty ones with a lump of coal. 

QUO has a similar “sweep” process: a mechanism that systematically goes through every Onion page to check whether it contains inappropriate content. If it does, the URL is blacklisted to prevent it from being viewed from within the index. Staggeringly, 18 out of every 20 dark web websites are blacklisted.

The Index

If Santa’s sack is considered the holy grail of the operation which ensures every child wakes up with a toy under their tree on christmas morning, then QUO’s index is of similar importance. Without the index, QUO would not be of much use as this database contains all the relevant information for each page visited by the crawler. So just like Santa’s sack not being correctly filled, if QUO’s index is missing information, both operations would likely fail.

So there you go: Who knows what would become of Christmas morning if all these processes in place in Santa’s workshop don’t run like clockwork. The same could be said for QUO: If all the elements and checks don’t work efficiently, the platform would likely fail and provide a place for the darker side of the dark web to flourish.

Figure 2: QUO’s homepage

Haven’t we been here before?

Although it may seem that services like Kilos and Recon already fulfil a similar function for the cybercriminal community, QUO is a different beast altogether. If we take a quick look at the stats below, we can see that both Kilos and Recon serve the same purpose for a select audience, i.e. indexing dark web data for the dark web cybercriminal community.


  • 25,000 vendors
  • 44,000 marketplace listings
  • 1.9 million reviews


  • 7,000 vendors
  • 109,000 marketplace listings
  • 1.45 million reviews
  • 877,000 forum posts

Whereas QUO has taken on the mantle of indexing as much of the dark web as is possible to become a useful resource for dark web users, researchers, curious individuals, and the alike.

To date, the platform states they have crawled “millions” of pages across “20k” sites with no specific audience in mind. Essentially, Kilos and Recon are useful to those interested or researching cybercriminal platforms, where QUO is useful to those simply interested in the dark web.

Wrapping things up….

Whatever your Christmas wish is this year, if you’re marked as “naughty” on either Santa’s list or QUO’s, then you’re likely to end up with coal in your stocking… 

If you’re interested in learning more about the dark web, see our overview on the dark web.