PR.AA-02: Identities are proofed and bound to credentials based on the context of interactions

The target keyword for this requirement page is: pr.aa-02: identities are proofed and bound to credentials based on the context of interactions requirement.

PR.AA-02 sits in the “Protect” function of NIST CSF and forces a practical discipline: you cannot treat identity proofing as a one-time checkbox, and you cannot treat credentials as generic tokens that float between people, systems, or contexts. The identity (person, service, device, or organization) must be validated to an appropriate standard, and the credential (password, key, certificate, token, authenticator, API key) must be issued and managed in a way that maintains a reliable link back to that validated identity.

For a Compliance Officer, CCO, or GRC lead, the fastest path to operationalizing PR.AA-02 is to (1) define “context of interactions” in your environment, (2) set proofing requirements per context, (3) ensure credential issuance and lifecycle management enforce identity binding, and (4) collect evidence continuously. This is less about picking a single “best” identity proofing method and more about having a defensible, consistent, and testable approach that matches risk and withstands audit scrutiny ¹.

Regulatory text

Excerpt: “Identities are proofed and bound to credentials based on the context of interactions” ².

Operator interpretation (what you must do):

1. Define interaction contexts that matter (e.g., external customer login, workforce privileged access, third-party remote support, service-to-service API calls).
2. Set proofing strength requirements per context (what evidence you require to establish identity).
3. Issue credentials only after proofing and record the linkage (who/what was proofed, how, when, by whom, and which credential was issued).
4. Maintain the binding over time through credential lifecycle controls (rotation, revocation, re-issuance, and reassignment prohibitions) and through monitoring for signals that require re-proofing.

This requirement is satisfied when an auditor can trace a credential back to a proofed identity and show that the proofing rigor matched the risk of the interaction ¹.

Plain-English interpretation

PR.AA-02 means: match identity proofing to risk, then make the credential traceable to the verified identity for its entire life.

• “Proofed” means you performed checks to establish the identity is who/what it claims to be.
• “Bound to credentials” means the credential was issued to that proofed identity, cannot be casually transferred, and remains attributable in logs and records.
• “Context of interactions” means the required rigor changes based on what is being accessed, the sensitivity of data, the privileges granted, and the threat exposure (external vs internal, automated vs human, production vs non-production) ¹.

Who it applies to (entity and operational context)

Entities: Any organization operating a cybersecurity program that manages user, device, workload, or third-party identities ¹.

Operational contexts where PR.AA-02 shows up in audits:

• Workforce access (employees, contractors)
• Privileged access (admins, break-glass accounts)
• Third-party access (support vendors, MSPs, outsourced developers)
• Customer identity and access (CIAM) for portals and apps
• Service accounts and workload identities (automation, CI/CD, microservices)
• Device identities (certificates, MDM enrollment, managed endpoints)

If you have “shared accounts,” informal account creation, or unmanaged API keys, PR.AA-02 will be hard to defend.

What you actually need to do (step-by-step)

Step 1: Define “context tiers” and map them to systems

Create a simple tier model your operators can use consistently:

Context tier	Typical interactions	Risk drivers	Proofing/credential expectation
Low	Access to public or non-sensitive internal info	Low impact if misused	Basic proofing; standard credential issuance controls
Medium	Access to internal systems with business data	Material confidentiality/integrity impact	Stronger proofing; MFA; tighter issuance controls
High	Privileged access, regulated data, production changes, payment flows	High impact, high abuse value	Highest proofing rigor; phishing-resistant auth where feasible; strict issuance and exception handling

Your tiering must be documented and tied to an inventory: which apps, APIs, admin consoles, and remote access paths fall into each tier ¹.

Step 2: Establish an identity proofing standard per identity type

Write a standard that answers, for each identity type, what evidence you accept and who approves exceptions:

• Human workforce: HR record + verified onboarding workflow, or equivalent.
• Third parties: contractual identity vetting, sponsor approval, and documented proofing steps before access is granted.
• Service/workload identities: ownership (system/app owner), purpose, environment scope, and technical proofing (e.g., issuance from trusted platform, controlled secret distribution).
• Devices: enrollment checks, asset assignment, and certificate issuance rules.

Keep it operational: define required fields, acceptable sources, and the minimum verification steps by tier ¹.

Step 3: Bind proofed identities to credentials through controlled issuance

Binding fails most often at issuance. Put controls there:

• Centralize issuance through your IAM/IdP, PKI, PAM, or secrets manager workflows.
• Require a sponsor/owner for every non-human identity (service accounts, API keys, certificates).
• Prohibit credential sharing and reassignment without re-proofing and re-issuance.
• Log issuance events: request, approval, proofing completion, credential creation, delivery method, and activation.

For third-party accounts, binding should include: third party organization, named individual, sponsor, ticket/request ID, and terms (time-bound, scope-bound).

Step 4: Enforce lifecycle controls that preserve the binding

Identity proofing and binding degrade as people change roles and systems drift. Minimum lifecycle expectations:

• Joiner/mover/leaver process: access changes track HR events and third-party offboarding.
• Credential rotation and revocation: rotate keys/secrets; revoke on termination, contract end, compromise, or role change.
• Re-proofing triggers: require re-proofing when high-risk signals appear (e.g., suspicious access patterns, account recovery, identity attribute changes, long dormancy).
• Periodic attestations: owners attest that accounts and non-human credentials remain required and correctly attributed.

Tie these to workflows and evidence, not tribal knowledge ¹.

Step 5: Implement exception handling that auditors can accept

You will have edge cases: incident response, break-glass, legacy systems, urgent vendor support. Define:

• Who can approve exceptions
• Maximum duration and scope
• Compensating controls (e.g., session recording, just-in-time access, ticket linkage)
• Post-event review requirements

An exception without a record is indistinguishable from a control failure during an audit.

Required evidence and artifacts to retain

Auditors will ask you to prove both design (policy/standard) and operation (records/logs). Retain:

Governance artifacts

• Identity Proofing and Credential Binding Standard (mapped to context tiers) ¹
• Access control policy section covering credential issuance, reassignment prohibition, and third-party access
• RACI showing control owner(s): IAM, Security, HR, Procurement/TPRM, App owners

Operational evidence

• System inventory mapped to context tiers
• Samples of proofing records (workforce onboarding evidence, third-party vetting artifacts, device enrollment records)
• Credential issuance logs (IdP, PAM, PKI, secrets manager) showing identity-to-credential linkage
• Tickets/approvals for account creation and privilege grants
• Joiner/mover/leaver records with correlated deprovisioning evidence
• Exception register (break-glass, emergency access, legacy shared access) with approvals and reviews
• Periodic access reviews/attestations for high-risk tiers

If you want this to run without heroics, assign an owner and set recurring evidence pulls. Daydream is often used here to map PR.AA-02 to a control owner, track evidence requests, and keep a living audit packet aligned to the requirement language ².

Common exam/audit questions and hangups

Expect variations of:

• “Show me how you determine proofing requirements based on interaction context.”
• “Pick a privileged user and trace their identity proofing through credential issuance to current access.”
• “How do you prevent credential sharing and reassignment?”
• “How do you manage service accounts and API keys so they remain attributable to an owner and purpose?”
• “Show third-party onboarding/offboarding for remote access.”
• “What triggers re-proofing or re-issuance?”

Common hangup: teams can describe the process but cannot produce records that connect proofing to a specific credential instance.

Frequent implementation mistakes and how to avoid them

1. Single-tier proofing for everything. Fix: define tiers and write minimum requirements per tier, then map systems.
2. Shared accounts justified as “operational.” Fix: require named identities; for rare exceptions, use time-bound break-glass with approvals and logs.
3. Service accounts treated as second-class. Fix: require an owner, purpose, environment, and issuance path for every non-human credential.
4. Binding exists in theory but not in logs. Fix: ensure IAM/PAM/PKI/secrets tooling records request IDs, approvers, and issuance events.
5. Third-party access bypasses proofing. Fix: require sponsor approval and proofing evidence before provisioning; enforce offboarding based on contract end.

Enforcement context and risk implications

No public enforcement cases were provided in the supplied source catalog for PR.AA-02, so this page does not cite enforcement actions.

Risk still matters operationally: weak proofing and poor binding lead to account takeover, unauthorized access by former staff or third parties, and non-attributable actions in sensitive systems. The compliance impact is predictable: you fail to demonstrate that access is tied to a validated identity, and investigators treat activity logs as unreliable for attribution and incident reconstruction ¹.

A practical 30/60/90-day execution plan

First 30 days (establish the rulebook and scope)

• Name a control owner for identity proofing and credential issuance across workforce, third party, and non-human identities.
• Define context tiers and draft the Identity Proofing and Credential Binding Standard.
• Inventory the highest-risk interaction paths: privileged admin access, remote access, third-party access, production access, and key APIs.
• Identify known gaps: shared accounts, unmanaged API keys, manual account creation, missing offboarding.

Days 31–60 (implement controls where risk is highest)

• Put privileged access under PAM or equivalent controlled workflow; require traceable issuance and approvals.
• Implement or tighten third-party onboarding: sponsor required, proofing steps recorded, time-bounded access, and offboarding triggers.
• Stand up non-human identity controls: owner + purpose + issuance workflow for service accounts and secrets.
• Build an evidence pack template: one privileged identity trace, one third-party trace, one service account trace, plus logs and approvals.

Days 61–90 (operationalize, test, and make it repeatable)

• Run access reviews for high-tier systems and remediate findings.
• Test incident scenarios: break-glass use, account recovery, and re-proofing triggers. Capture evidence.
• Formalize exception handling and ensure every exception has an approver, scope, and expiration.
• Automate recurring evidence collection where possible; Daydream can track control mapping, requests, and artifacts so PR.AA-02 stays audit-ready between assessments.

Frequently Asked Questions

Does PR.AA-02 require identity proofing for internal employees?

Yes, if employees access systems where misuse would matter. You should define proofing expectations tied to onboarding and role changes, then show that credentials were issued only after those steps were completed ¹.

How do I handle service accounts and API keys under PR.AA-02?

Treat them as identities with owners. Require a documented owner, purpose, scope, and a controlled issuance path through a secrets manager or equivalent so the credential remains attributable and revocable ¹.

Is MFA enough to satisfy “proofed and bound”?

MFA strengthens authentication but does not replace proofing or binding. You still need evidence that the identity was validated appropriately and that the credential presented is linked to that identity through controlled issuance and lifecycle management ¹.

What’s the minimum evidence an auditor will accept?

A traceable chain: proofing record → approval/request → credential issuance log → current access/role assignment. If any link is missing, expect follow-up testing or a control finding.

How should third-party access be proofed?

Require a sponsor inside your organization, verify the third party individual’s identity per your tiering, and bind their access to a named account with time limits and offboarding tied to contract end or task completion ¹.

What if legacy systems force shared credentials?

Document an exception with an expiration, compensating controls (tight network scope, session logging where possible, ticket-based check-out), and a migration plan to named accounts. Auditors focus on whether you controlled and time-bounded the risk, not whether the legacy system is inconvenient.

Footnotes

1. NIST CSWP 29

2. NIST CSWP 29; NIST CSF 1.1 to 2.0 Core Transition Changes