IA-8(6): Disassociability

To meet the ia-8(6): disassociability requirement, you must design your digital identity and authentication flows so a relying party cannot easily correlate a person’s activity across systems, and so identity attributes are not unnecessarily linkable between the individual, the credential service provider (CSP), and the relying party. Operationally, this means minimizing shared identifiers, limiting attribute release, and controlling logging and federation mappings.

Key takeaways:

• Reduce linkability by avoiding global, static identifiers across relying parties; prefer per-relying-party identifiers.
• Enforce attribute minimization in federation and authentication, and prove it with configuration evidence and test results.
• Treat logs, correlation IDs, and federation “joins” as in-scope; disassociability fails most often in observability tooling.

IA-8(6) sits in the NIST SP 800-53 “Identification and Authentication” family and focuses on privacy-preserving identity: preventing unnecessary correlation of a person’s identity and attributes across credential providers and relying parties. The requirement is easy to misunderstand because teams often treat it as a purely “federation” control (SAML/OIDC), while auditors frequently look for system-wide linkability paths: identifiers, attributes, and event trails that allow correlation.

For a CCO or GRC lead, the fastest path to operationalize IA-8(6) is to convert it into concrete design rules for identity architecture and evidence you can hand an assessor. That means: (1) decide where disassociability is required (which applications, tenants, partners, and authentication methods), (2) pick a technical pattern (pairwise pseudonymous identifiers, attribute release policies, token design), and (3) continuously prove the pattern is enforced with configuration snapshots, tests, and change control records.

This page translates the ia-8(6): disassociability requirement into steps you can assign to IAM, security engineering, and application owners, with a tight evidence list and audit questions you can pre-answer.

Regulatory text

NIST requirement (excerpt): “Implement the following measures to disassociate user attributes or identifier assertion relationships among individuals, credential service providers, and relying parties: {{ insert: param, ia-08.06_odp }}.” ¹

Operator meaning: NIST expects you to implement specific, defined measures (your organization must select and document them) that break or reduce correlation between:

• Individuals (the person),
• Credential Service Providers (CSPs) (IdP/identity provider, authentication service),
• Relying Parties (RPs) (apps, services, partners that consume identity assertions).

In practice, you must be able to show (a) what “measures” you chose, (b) where they apply, and (c) evidence they work and remain in place through change.

Plain-English interpretation (what IA-8(6) is asking for)

IA-8(6) requires disassociability: a relying party should not get more ability than necessary to link a user’s identity, attributes, or activity across contexts. Put differently: your identity system should avoid creating a universal “join key” that lets different apps, partners, or environments stitch a person’s history together.

Disassociability usually breaks down into three control outcomes:

1. Identifier separation: Each relying party gets an identifier that is not trivially linkable to identifiers used elsewhere.
2. Attribute minimization: Relying parties receive only the attributes required for the transaction or authorization decision.
3. Correlation-resistant telemetry: Your logs and tokens do not unintentionally reintroduce a cross-system join key.

Who it applies to (entity and operational context)

IA-8(6) is relevant wherever you implement federated identity, shared authentication, or centralized IAM for:

• Federal information systems and contractor systems handling federal data (common drivers include NIST-based ATO packages and contract security requirements). ²

Operational contexts where IA-8(6) typically becomes “exam-visible”:

• SAML or OIDC federation between an enterprise IdP and multiple applications.
• B2B integrations where partners rely on your identity assertions.
• Multi-tenant SaaS where the same person might exist across tenants.
• Centralized logging/analytics that ingests authentication and application events.

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

Step 1 — Define scope and the “disassociability boundary”

Create an IA-8(6) scope statement that names:

• CSP/IdP platforms (for example: enterprise IdP, customer IAM).
• Relying parties (internal apps, SaaS, partner portals, APIs).
• Identity proofing level assumptions if relevant to your environment.
• Data classes involved (attributes released, identifiers in tokens, audit logs).

Output: IA-8(6) applicability matrix (CSP → RP mappings).

Step 2 — Choose concrete “measures” that you will implement and test

Because the control text references an organization-defined parameter, you must pick explicit measures and document them. Common measures that map cleanly to technical settings:

A. Per-relying-party identifiers (preferred)

• Configure federation to issue pairwise / sector-specific subject identifiers (OIDC “pairwise sub” or equivalent pattern).
• Avoid sending employee ID, email, or other stable enterprise identifiers as the primary subject where disassociability is required.

B. Attribute release policy

• Define a standard: “release minimum attributes required,” with named attribute bundles by use case (authentication only vs. authorization vs. provisioning).
• Enforce via IdP attribute mapping rules (and block ad hoc attribute additions outside change control).

C. Token and assertion design

• Ensure tokens/assertions do not embed extra identifiers that allow correlation (for example: multiple identifiers at once).
• Keep token audiences tight (RP-specific) and avoid reusing the same token across multiple RPs.

D. Logging and correlation controls

• Review IdP logs, app logs, SIEM fields, and APM traces for stable identifiers.
• Where correlation is needed internally, control it: limit access, apply retention rules, and avoid exporting join keys to relying parties or third parties.

Decision tip: If you can implement only one measure quickly, start with per-RP identifiers, because it reduces linkability even if some attributes still flow.

Step 3 — Convert measures into enforceable engineering requirements

Write short, testable requirements your teams can implement, for example:

• “RPs must not receive a globally unique enterprise identifier unless approved and documented.”
• “IdP attribute release for RP X is limited to attributes A, B, C.”
• “Subject identifier format for RP X must be pairwise and non-reversible outside the CSP.”

Tie each requirement to:

• System owner,
• Implementation location (IdP config, gateway policy, app code),
• Change control mechanism.

Step 4 — Implement configuration guardrails

Put guardrails where change happens:

• IdP configuration baselines for each RP connection (SAML app, OIDC client).
• Template-driven onboarding for new RPs so “pairwise identifier + minimal attributes” is the default.
• Approval workflow for exceptions (business justification, risk sign-off, and time-bound review).

If you use Daydream for third-party and control operations, treat each relying party as an onboarding object with required artifacts (attribute map, identifier policy, test evidence) so you can prove the control repeatedly without rework.

Step 5 — Validate with tests that an assessor will accept

Run and retain repeatable tests:

• Authenticate the same user to two different RPs and verify the RP-visible subject differs where required.
• Inspect assertions/tokens for attribute minimization.
• Confirm logs accessible to RP operators do not expose a stable join key across RPs.

Make these tests part of:

• New RP onboarding,
• Quarterly (or change-triggered) control checks,
• Post-incident validation if identity systems changed.

Step 6 — Operationalize monitoring and exception handling

Disassociability breaks during “small” changes: new claim added, new logging field, new downstream integration. Create:

• A lightweight exception register for RPs that require correlatable identifiers.
• A periodic review of RP attribute release and identifier strategy.
• Detection rules for “new attribute added” or “identifier changed” in IdP configurations (or configuration drift alerts).

Required evidence and artifacts to retain

Auditors will ask for proof the measures are implemented and sustained. Keep:

Design & governance

• IA-8(6) scope statement and applicability matrix (CSPs, RPs, environments).
• Written “disassociability measures” standard (the organization-defined choices).
• Attribute classification and approved attribute bundles by RP type/use case.

Technical configuration evidence

• IdP screenshots/exports: per-RP identifier settings, subject mapping, attribute release mappings.
• Example SAML assertions / OIDC ID tokens for key RPs (sanitized) showing subject and claims.
• Change tickets for RP onboarding and for any attribute/identifier change.

Testing & operations

• Test scripts and results demonstrating subject disassociation across RPs where required.
• Exception register with approvals and review notes.
• Access controls for logs/telemetry that contain identifiers (role mappings, permissions evidence).

Common exam/audit questions and hangups

1. “Show me the measures you selected for IA-8(6).”
   Hangup: teams implement technical changes but never write the organization-defined measures down.

2. “Which relying parties get which identifiers and attributes?”
   Hangup: no authoritative mapping; app owners add attributes informally.

3. “Can RP A and RP B correlate the same person?”
   Hangup: email address or employee ID appears in both tokens, or is present in RP-visible logs.

4. “How do you prevent drift?”
   Hangup: no recurring review, no config monitoring, no onboarding template.

Frequent implementation mistakes (and how to avoid them)

• Mistake: Treating email as a safe identifier.
  Fix: treat email as a strong correlator; only release it when required, and document the justification.

• Mistake: Pairwise subject IDs, but you also send a stable secondary identifier.
  Fix: scan tokens/assertions for “extra” identifiers (employee ID, UPN, immutableId). Make “no secondary stable IDs” the default.

• Mistake: Disassociability in auth, but not in logs.
  Fix: review SIEM/APM exports and RP admin consoles. Control who can see correlation IDs and whether they are shared across apps.

• Mistake: No exception discipline.
  Fix: keep a register with RP name, rationale, attributes/IDs shared, compensating controls, and periodic review.

Risk implications (why operators care)

If you do not disassociate identifiers and attributes, you increase:

• Privacy risk (unnecessary profiling and correlation across services).
• Breach impact (a compromised RP can become a pivot for correlating identities elsewhere).
• Contract and ATO risk for federal workloads tied to NIST control expectations. ²

Practical 30/60/90-day execution plan

First 30 days (triage and baselines)

• Inventory CSPs/IdPs and all relying parties that consume assertions.
• Capture current per-RP attribute mappings and subject identifier formats.
• Draft your IA-8(6) “measures” statement (the organization-defined parameter content) and get security and privacy sign-off.
• Pick a pilot set of high-risk RPs (external-facing, partner-integrated, or multi-tenant).

Days 31–60 (implement controls where it matters)

• Implement per-RP identifiers for pilot RPs where feasible.
• Enforce attribute release bundles and block ad hoc additions.
• Establish an exception workflow with required fields and approvals.
• Build a repeatable token/assertion inspection test and store results with the RP record (Daydream can act as the system of record for artifacts and renewals).

Days 61–90 (scale and make it auditable)

• Roll the pattern into the RP onboarding process (templates, checklists, required evidence).
• Add configuration drift detection and a periodic review cadence for attribute mappings.
• Run an internal mini-assessment: pick multiple RPs, prove disassociability with test outputs, then trace back to change tickets and approvals.
• Train app owners on “requesting attributes” and the exception process.

Frequently Asked Questions

Does IA-8(6) mean we must anonymize all users?

No. IA-8(6) focuses on preventing unnecessary linkability between individuals, CSPs, and relying parties. You can still identify users where the business purpose requires it, but you should avoid cross-service join keys by default. ¹

We use OIDC. What is the fastest technical win for disassociability?

Configure pairwise subject identifiers per relying party where your IdP supports it, and remove stable secondary identifiers from the ID token unless approved. Then prove it with two-token comparisons from different relying parties.

Are logs in scope for IA-8(6)?

Usually, yes in practice, because logs often contain the identifiers and attributes that enable correlation. If relying party operators or third parties can access those logs, treat that as part of the “identifier assertion relationship” you must control. ¹

How do we handle cases where multiple relying parties must share an identifier (e.g., fraud or support)?

Document an exception with rationale, list the exact identifiers/attributes shared, and add compensating controls such as tighter access controls and limited distribution. Re-approve the exception on a defined cadence tied to your risk process.

What evidence is most persuasive to an assessor?

A clear measures statement, per-RP configuration exports (identifier mapping + attribute release), and a simple test showing the same user authenticating to two RPs with non-linkable identifiers. Tie each artifact to a change record and an owner.

How should we operationalize IA-8(6) across third parties that act as relying parties?

Treat each third party RP like a controlled integration: require an attribute/identifier schedule, security review, and ongoing evidence refresh. Daydream is useful here because it can track each third party integration’s required artifacts, exceptions, and revalidation tasks in one place.

Footnotes

1. NIST SP 800-53 Rev. 5 OSCAL JSON

2. NIST SP 800-53 Rev. 5