Toll fraud, also known as International Revenue Sharing Fraud (IRSF), is a significant issue that leads to $10 billion in annual revenue losses globally. It involves teams of criminals exploiting apps by placing calls to international premium rate numbers, which can result in a virtual wire-transfer from the company's bank account to theirs. Twilio has developed a dynamic solution to help protect applications from toll fraud, including classifying destinations according to risk and enabling low-risk permissions for most businesses. To further reduce risk, users can navigate to the Geo Permissions High-Risk tab and de-select countries with high-risk checkboxes enabled, while being cautious not to disable the low-risk tab. Additionally, Twilio provides guidance on detecting blocked calls and understanding which permission group is required to call a particular phone number.