There is proposed a method for executing a workflow, comprising providing the workflow comprising process level activities, at least one process level activity being able to access system resources, the access to the system resources being mediated by a plurality of backend modules. A backend module of the plurality of backend modules carries out the steps of receiving a hierarchical attribute certificate, validating the attribute certificate, checking whether the attribute certificate grants a right to execute the backend module, checking whether a predefined execution path from the process level activity to the backend module has been traversed, and if both checking steps are successful, executing the backend module. Moreover, there is proposed a respective device, computer program medium and computer program product.