Building Cyber Confidence: ASEAN’s Defence Diplomacy through ADMM-Plus

Abstract

Digital transformation in Southeast Asia has enhanced regional connectivity while creating new vulnerabilities to complex, cross-border cyber threats. This situation has prompted ASEAN to develop cybersecurity cooperation mechanisms, including those within the ASEAN Defence Ministers’ Meeting Plus (ADMM-Plus) framework. This study analyzes how the ADMM-Plus, specifically the Experts’ Working Group on Cyber Security (EWG-CS), addressed regional cyber threats between 2017 and 2025 through the lens of Confidence-Building Measures (CBMs). Using a qualitative case study approach, the study analyzes secondary data from official ASEAN and ADMM-Plus documents, policy reports, and academic literature, complemented by a semi-structured interview with an official from Indonesia’s National Cyber and Crypto Agency (BSSN). The findings show that the EWG-CS operationalizes CBM functions through sustained dialogue, information and knowledge exchange, capacity building, and institutional interaction among ASEAN Member States and Plus Countries. These practices have generated institutional mechanisms and collaborative outputs across three co-chairmanship cycles, including points-of-contact arrangements, technical personnel networking, cyber terminology standardization, cyber exercises, training programs, and the Cyber Security Framework. The BSSN interview further indicates that international cybersecurity cooperation contributes to Indonesia’s national cybersecurity by facilitating knowledge transfer, strengthening capacity, expanding institutional networks, and supporting cyber resilience. Rather than directly preventing or responding to cyberattacks, the EWG-CS functions as a defense diplomacy platform that reduces uncertainty, builds trust, and facilitates sustained regional cybersecurity cooperation.