ISM: Australian Government Information Security Manual

The Australian Government Information Security Manual (ISM) is the comprehensive information security reference published by the Australian Signals Directorate (ASD). It provides a cybersecurity framework for Australian government entities and their contractors, covering everything from governance and personnel security to technical controls and cryptographic standards. The ISM is updated regularly to address emerging threats and incorporates the Essential Eight — ASD's prioritized list of mitigation strategies.

What the ISM Covers

The ISM contains over 800 security controls organized into categories including cybersecurity governance, personnel security, physical security, communications security, information technology security, media security, software security, email security, network security, cryptographic security, gateway security, data transfer security, and enterprise mobility security.

At the heart of the ISM is the Essential Eight — eight prioritized mitigation strategies that address the majority of cyber incidents: application control, patching applications, Microsoft Office macro settings, user application hardening, restricting administrative privileges, patching operating systems, multi-factor authentication, and regular backups. The Essential Eight has a maturity model from Level Zero to Level Three.

Who Needs ISM Compliance

The ISM applies to all Australian government entities at the federal level and is increasingly adopted by state and territory governments. Defense contractors and companies handling Australian government information must align with ISM requirements as specified in their contracts. The Essential Eight is mandated for all non-corporate Commonwealth entities. Organizations seeking to sell to the Australian government benefit from demonstrating ISM alignment.

Implementation Approach

Start with the Essential Eight, targeting Maturity Level Two as a minimum for most organizations. Conduct a gap assessment against applicable ISM controls for your system's security classification. Implement controls proportionate to the classification level — OFFICIAL systems require a baseline set, while PROTECTED and above require progressively more stringent controls. Complete system security documentation including a System Security Plan and obtain authorization to operate.

Cost Considerations

ISM compliance costs range from $30,000 for focused Essential Eight implementation at Maturity Level Two to $300,000 or more for comprehensive ISM compliance at higher classification levels. Defense contractors and companies handling PROTECTED information face the highest costs due to cryptographic requirements, personnel clearances, and physical security controls. The Essential Eight Maturity Model provides a practical, prioritized starting point for reducing compliance costs while maximizing security effectiveness.