AP
Fighters from the Islamic State group parade in a commandeered Iraqi security forces armored vehicle down a main road at the northern city of Mosul, Iraq.
Chris Vickery claimed on Reddit that he had managed to gain access to a mid-2o14 version of the World-Check database, and also talked about the data to tech news site The Register.
Word-Check, which is owned by Thomson Reuters, is used by hundreds of governments and spy agencies, and most of the world's biggest banks and law firms.
"The current-day version of the database contains, among other categories, a blacklist of 93,000 individuals suspected of having ties to terrorism," Vickery wrote on Reddit. "[The] copy [obtained by the researcher] has over 2.2 million heightened-risk individuals and organizations in it. The terrorism category is only a small part of the database. Other categories consist of individuals suspected of being related to money laundering, organized crime, bribery, corruption, and other unsavory activities."
The researcher says he is considering leaking the alleged database, and that it was not obtained by hacking: "I would call it more of a leak than anything, although not directly from Thomson Reuters. The exact details behind that can be shared at a later time."
It's possible that it was leaked via one of World-Check's customers - either deliberately or accidentally.
It's not clear whether anyone other than Vickery has had access to the data, and Business Insider has not seen the alleged database. But Chris Vickery has a good track record on tracking down leaked datasets. Earlier this month, he unearthed a huge cache of 154 million of US voter records.
He has also found databases containing millions of Hello Kitty customers, more than 10 million MacKeeper customers' data, and more.
Thomson Reuters did not immediately respond to Business Insider's request for comment.
The World-Check database, which is compiled from public sources, has previously proved controversial. A February 2016 investigation from Vice News claimed that there were numerous individuals on the list with a "terrorism" designation that appeared to be there erroneously, including "an American Muslim civil rights leader praised by George W. Bush, an economist honored by the British Queen, and a prominent anti-extremism campaigner."
Banks and other organisations can use the list to vet customers, so appearing on it wrongly could have a serious impact on how individuals and businesses can operate. Similarly, a public release of the data could have the potential to be massively reputationally damaging to those on the list.