AC-20 (01) Limits on Authorized Useac-20.1
Whether an AWS call fetches evidence for this control, and what to run. Its Rev5 baselines, the indicators that reach it and the FedRAMP guidance attached to it open below.
Nothing names itNo recipe names AC-20 (01). 20 reach an indicator it shares, which is adjacency and not coverage — worth reading, not worth recording as evidence for this control.
Collect evidence (0)
Authored AWS and pipeline recipes whose output is evidence for AC-20 (01). This mapping is this project’s opinion (AWS overlay v3.0.0, pipeline overlay v0.8.0), versioned separately from the dataset — the upstream FedRAMP rules name none of these tools.
No authored recipe names AC-20 (01). The nearest authored work is below.
The enhancement asks for verification that the EXTERNAL system implements the required controls, or a retained agreement saying so — a statement about somebody else's estate that no call against this one can make.
This project’s assessment (automation register v0.9.0, reviewed 2026-08-04), versioned separately from the dataset and from the evidence overlays. It is an opinion about the AWS surface on that date, and the surface moves.
The KSIs that reach it are KSI-CNA-MAT, KSI-IAM-ELP, KSI-IAM-JIT, KSI-MLA-LET, KSI-MLA-OSM — which is what asks for it. The evidence it asks for is written, not fetched. Browse /collect for the whole authored corpus.
Reaches the same indicator, not AC-20 (01)
These recipes prove a KSI that reaches it. None of them claims AC-20 (01) — treat them as neighbours worth reading, not as coverage.
- Every route in or out of the boundary, named and counted — internet gateways, NAT gateways, VPC endpoints and Site-to-Site VPN tunnels — alongside what each boundary device does with traffic that matched no rule: the network ACL entries, the closed default security group, subnets that hand out public IPs, and the firewall policy's stateless and stateful default actions via KSI-CNA-MATaws
- Which taint-tracking ruleset actually ran over this repository — the query suite, the languages selected, and the threat model that decides what counts as an untrusted source — together with whether the recurring scan is still scheduled, when it last ran per analysed language, and how many rules were in the run; and then the open findings in the injection families SI-10 is about, identified by the CWE tags the queries carry. The ruleset and the freshness are the load-bearing half: a finding names a sink that exists, but only the run record says the absence of findings means anything at all. via KSI-CNA-MATpipeline
- Whether the queries that find information disclosure through an error message or a stack trace ran over this part of the boundary — which languages were selected, whether the recurring scan is still scheduled and when it last completed — and then the open findings those queries produced, identified by the CWE tags the queries carry rather than by their names. The run record is the load-bearing half here as it is on every scanning recipe: a finding names a leak that exists, and only the record of a scan having run over a selected language makes the absence of findings a statement about anything. via KSI-CNA-MATpipeline
- Account-wide credential report proving MFA is active per principal and that passwords/access keys are rotated within policy via KSI-IAM-ELPaws
- Full snapshot of every IAM user, group, role, and attached/inline policy with their relationships, used to review that granted permissions match least-privilege intent via KSI-IAM-ELPaws
What NIST requires of AC-20 (01)
The control statement from NIST 800-53 Rev5, verbatim. Square brackets are organization-defined parameters — yours to set, not FedRAMP's to dictate.
Permit authorized individuals to use an external system to access the system or to process, store, or transmit organization-controlled information only after: (a) Verification of the implementation of controls on the external system as specified in the organization’s security and privacy policies and security and privacy plans; or (b) Retention of approved system connection or processing agreements with the organizational entity hosting the external system.
NIST SP 800-53 Rev5 catalog 5.2.0, from usnistgov/oscal-content at 78650f0. The FedRAMP dataset carries no control text; this is borrowed and pinned.
Rev5 baseline membership
Membership is the whole relationship — a baseline is a set of control ids. Class A carries no baseline at all. The Low/Moderate/High labels are an interpretation from control counts, not a dataset fact.
KSI indicators reaching this control (5)
Under 20x, these indicators are how this control is demonstrated — automated KSI evidence stands in for narrative control evidence.
- CNAKSI-CNA-MATMinimizing Attack Surface
Machine-based information resources are persistently reviewed to ensure they have a minimal attack surface and that lateral movement is minimized if compromised.
- IAMKSI-IAM-ELPEnsuring Least Privilege
Identity and access management measures are used and persistently reviewed to ensure each user or device can only access the resources they need.
- IAMKSI-IAM-JITAuthorizing Just-in-Time
A least-privileged, role and attribute-based, and just-in-time security authorization model is used and persistently reviewed for all user and non-user accounts and services.
- MLAKSI-MLA-LETLogging Event Types
A list of information resources and event types that will be logged, monitored, and audited is maintained and persistently reviewed to ensure these activities occur.
- MLAKSI-MLA-OSMOperating SIEM Capability
A Security Information and Event Management (SIEM) or similar system(s) is used and persistently reviewed for centralized, tamper-resistant logging of events, activities, and changes.
Pages exist for the 209 controls reached by at least one KSI. Baseline-only controls are the orphans on /coverage. Control titles and full text live in the NIST catalog, not this dataset.