ISM stands for the Information Security Manual, the Australian government’s baseline guidance for protecting information and systems. It defines practical security controls for areas such as identity, patching, logging, network segmentation, encryption, backup, and incident response. Agencies and vendors use it to judge whether a system is suitable for government workloads, especially when handling sensitive or classified data.
In cyber security, the ISM matters because it turns high-level policy into auditable controls. During cloud adoption, it helps teams decide what can be inherited from a provider and what must still be configured, monitored, and approved by the agency. Defenders use the ISM as a checklist for hardening environments and proving assurance; attackers benefit when those controls are weak, missing, or inconsistently applied. For government buyers, ISM alignment is often a key part of risk acceptance and authorisation.