STR is Brazil’s real-time gross settlement system for irrevocable interbank transfers. A real-time gross settlement system settles payments individually, with finality, instead of netting them later. “Irrevocable” means that once a transfer is accepted and settled, it is meant to be final and not easily reversed.
In cyber security, STR matters because it sits at the high-trust end of the payment chain. If attackers obtain valid credentials, transaction privileges, or access to payment integrations, they may be able to move money through legitimate rails rather than malware-driven fraud. That makes detection harder: traffic can look like normal banking activity while funds are already committed. Defenders should protect STR-linked systems with strict access control, separation of duties, strong logging, and monitoring for unusual settlement patterns or privileged misuse.