Security-related information needs to be shared to cope with increasing amount of cyber attacks. We introduce a system, called DAEDALUS (Direct Alert Environment for Darknet And Livenet Unified Security), that monitors a large-scale darknet to secure live networks. It uses a large-scale distributed darknet consisting of several organizations, with which we can mutually observe outgoing malicious packets among one another. This paper presents the overview of the system, current status of this work toward practical deployment, and consideration on the usefulness of related standards.