Secondary sanctions are a very powerful tool. Even if you have no physical presence in the US, they can cut you off from the US Dollar system. This means no international bank will want to touch your money because they all deal with New York eventually. You should check the main website https://ofacblockedfundslawyers.com/ to see how these global enforcement actions work. If you are put on a list, you won’t be able to buy software from Microsoft, use credit cards, or even pay for international shipping. I know a small trade firm in Italy that went bankrupt in two weeks after they were flagged for a deal with a sanctioned entity. It doesn’t matter where you are based; if you use the global financial system, OFAC has power over you. Always vet your partners very carefully.