AC-20 Use of external systems
Requires terms to be established, or existing external system relationships identified, before authorized individuals may reach the system from external systems or handle organizational information on them, or alternativ
4
artefacts
0
held by a system
1
at each review
hard
to go live
Policy repository / GRC workspace
where the evidence lives
teal = a system already holds it · olive = produced at each review
system holds itEvidence a system already holds
none for this control
periodic reviewEvidence produced at each review
- Technical enforcement evidence such as blocked personal cloud storage or unmanaged device denial · Endpoint management (MDM / EDR)
governing documentDocuments that govern the control
- Documented terms and conditions or agreements covering permitted external system use · Policy repository / GRC workspace
- Register of external systems recognised as trusted and the basis for that trust · Policy repository / GRC workspace
- Policy statement naming external system types that are prohibited · Policy repository / GRC workspace
First move
This control is evidenced by people and documents, not systems. Put the document under version control with an owner and review date, and log each review as a record with reviewer and date. Do not try to automate it.
Common gaps auditors find
- Terms exist on paper while unmanaged home devices connect freely in practice
- Prohibited categories never enumerated, so nothing can be enforced or tested
- Trust relationships assumed from a commercial contract that never mentions security requirements
Do this for your whole sheet
Paste the rows you run your controls from and get this mapping for every control at once, with the periodic-review ones flagged and a first move per row. No account for the first run.
Build my evidence sheetAC-19 Access control for mobile devices · AC-21 Information Sharing. Enable authorized users to determine whether access authorizations assigned to a sharing partner match the information's access and use restrictions for [organization-defined] ; and Employ [organization-defined] to assist users in making information