Source code is not just technical material.
It is intellectual property, operational logic, and security control all in one.
Annex A 8.4 exists to ensure organisations strictly control access to source code and associated development tools, preventing unauthorised disclosure, modification, or misuse.
This control is about protecting the blueprint of your systems, not just the systems themselves.

Annex A 8.4 of ISO 27001:2022 focuses on controlling access to source code.
At a practical level, this means:
The control does not prevent development activity. It expects organisations to separate creation, access, and approval deliberately.
Source code often contains:
If access to source code is uncontrolled:
Annex A 8.4 ensures organisations treat source code as a high-value information asset, not just a development by-product.
This control replaces ISO 27001:2013 Annex A 9.4.5 and introduces stronger emphasis on tooling, auditability, and structured access control.
A pragmatic approach to Annex A 8.4 typically includes the following elements.
Organisations should clearly define what is considered source code, which may include:
Clear scope prevents accidental exclusion of critical material.
Access to source code should be:
Not everyone involved in IT requires direct access to source code.
Annex A 8.4 explicitly supports differentiated access.
Organisations should consider:
Write access carries significantly higher risk than read access.
Access to source code should be controlled centrally.
This typically involves:
Ad-hoc storage of code undermines control and traceability.
ISO 27001:2022 places emphasis on indirect access.
Organisations may:
Tooling can enforce discipline where policy alone cannot.
Access to source code should align with formal change control.
This includes:
Annex A 8.4 aligns closely with change management controls (see Annex A 8.32).
Organisations should maintain records of:
Audit trails support:
Untracked change is unmanaged change.
Source code repositories should be protected against:
This may include:
Protection should match the value of the code.
Where code is released or shared externally, organisations may consider:
This protects both the organisation and downstream users.
Annex A 8.4 does not require:
It does require organisations to:
Source code incidents are often catastrophic, not incremental.
Most source code compromise is preventable.
Annex A 8.4 is about protecting the organisation’s intellectual and operational core.
When access to source code is managed effectively:
Applications run the business.
Source code defines how they behave.
Annex A 8.4 ensures that behaviour is controlled, intentional, and defensible.
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