What should an IS auditor do FIRST upon discovering that a service provider did not...

The IS auditor should notify audit management of the finding first, as this is a significant issue that may affect the audit scope and objectives. The IS auditor should not notify law enforcement or require the third party to notify customers without consulting audit management first. The audit report with a significant finding should be issued after the audit is completed and the findings are validated. References: ISACA, CISA Review Manual, 27th Edition, 2018, page 247