On September 3, 2026, the Australian Signals Directorate published the September 2026 Information Security Manual (ISM) and its change log.

New controls address unique identities and maintained registers for AI agents; least privilege, task-scoped authorisation, untrusted external content and central logging for agentic AI; approved access paths and independent logging for service providers; short-lived and centrally managed credentials; immutable and segregated backups; quarterly threat hunting; pinned dependencies and reproducible software builds; and segregated network management interfaces.

ASD also amended ISM-2118 so vulnerability assessments and penetration tests are recommended at least every six months instead of annually. The ISM represents ASD advice and is not generally mandatory as a matter of law unless another legal instrument, lawful direction or binding arrangement requires compliance.

The update does not establish product homologation, certification, import or labeling obligations.

Impact

Impact assessment: Medium.

Key reasons: the update materially raises the recommended cybersecurity baseline for government, critical-infrastructure and enterprise environments, particularly for AI agents, privileged access, backups and assurance testing.

Who is affected?

CISOs, system owners, software teams, service providers, security assessors and IT/OT operators.

Conclusion:

organisations using the ISM should perform a control-gap assessment and update security plans, contracts and testing schedules.