I have read somewhere that ISIS mostly runs on cryptocurrency now because it's harder to block.

Oh here

> They delve in weapons and human trafficking, sometimes take part in drug smuggling, more and more engage in crypto mining and frauds related to the crypto industry - the whole Islamic State is now operating by crypto, whether it’s various European countries, West or East Africa, Asia, or such weird places like Costa Rica, Brazil or Argentina.

https://saladinaldronni.substack.com/p/recent-islamic-state-...

edit:

but it seems they have mostly moved to Monero

https://gnet-research.org/2025/02/18/combating-islamic-state...