AC-2(9): Restrictions on Use of Shared and Group Accounts

AC-2(9) requires you to allow shared or group accounts only under tightly defined conditions you set (the organization-defined parameters), and to block or remediate all other shared access. Operationally, you need an inventory of shared/group accounts, documented approval criteria, compensating controls for accountability, and recurring reviews with evidence.

Key takeaways:

• Shared and group accounts must be the exception, not the default, and allowed only if they meet your defined restrictions. ¹
• Your approval standard must restore accountability (who did what) through compensating controls such as traceable attribution and strong authentication. ²
• Auditors look for two things: proof you know where shared accounts exist, and proof each one is justified, controlled, and periodically revalidated. ²

The ac-2(9): restrictions on use of shared and group accounts requirement is a practical control with a simple goal: prevent “anonymous administration” and untraceable actions that undermine investigations, change control, and least privilege. Shared accounts (one credential used by multiple people) and group accounts (account intended for a role or group) show up in real environments for legacy applications, operational handoffs, break-glass scenarios, third-party support access, and certain service desk workflows. They also create an immediate accountability gap unless you add guardrails.

NIST frames this as an access control enhancement under account management: you may permit shared and group accounts, but only if they meet organization-defined conditions. Those conditions are not optional. They are the core of the requirement and must be explicit enough that an operator can decide “approve” or “deny” consistently. The quickest path to operationalizing AC-2(9) is to (1) define your acceptance criteria, (2) find every shared/group account in scope, (3) either eliminate it or wrap it in compensating controls, and (4) run a review cadence that produces audit-ready evidence. ¹

Regulatory text

Requirement (excerpt): “Only permit the use of shared and group accounts that meet {{ insert: param, ac-02.09_odp }}.” ¹

Operator interpretation (what you must do)

• You must define the restrictions/conditions under which shared and group accounts are allowed (the “organization-defined parameters”).
• You must enforce those restrictions so shared/group accounts exist only when they meet your criteria.
• You must treat nonconforming shared/group accounts as findings: remove them, convert to named accounts, or implement compensating controls plus formal exception handling. ²

Plain-English interpretation

Shared and group accounts reduce accountability. AC-2(9) allows them only when you can defend the business need and still answer: who accessed what, when, from where, and what they changed. Your “restriction” can be a rule set such as: “shared accounts are allowed only for emergency break-glass, must be vaulted, must require MFA, must generate an individual checkout log, and must be reviewed regularly.”

This requirement is less about writing a policy and more about making shared access traceable. In practice, that means (a) defaulting to individual named accounts, and (b) when shared access is unavoidable, routing it through controlled mechanisms (PAM, vaulting, session recording, ticket linkage) so actions can be attributed to a person. ²

Who it applies to

Entities

• Federal information systems and programs using NIST SP 800-53 as a control baseline.
• Federal contractors and service organizations handling federal data or operating systems assessed against NIST SP 800-53. ²

Operational scope (where this shows up)

• Privileged access (sysadmin, database admin, cloud admin).
• Shared operational logins (NOC shifts, on-call handoffs).
• Third-party support access where the third party requests a generic credential.
• Legacy platforms that cannot support individual identities.
• Emergency/break-glass access paths. ²

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

Step 1: Write your “allowable shared/group account” standard (your ODP)

Create a short standard that an operator can apply without debate. Include:

1. Allowed use cases (e.g., break-glass only; legacy constraint with documented remediation plan; tightly scoped application operator role).
2. Prohibited use cases (e.g., routine admin; day-to-day user access; access to sensitive systems without attribution controls).
3. Required compensating controls (pick what fits your environment):
   • Credential vaulting / PAM checkout tied to a unique user
   • MFA enforced at checkout or at login
   • Session logging/recording for privileged use
   • Ticket requirement (change or incident) for each use
   • Time-bound access and automatic rotation after use
4. Approval authority (system owner + security; add compliance for high-risk systems).
5. Review and revalidation trigger (periodic review, plus event-based triggers like privilege change, owner change, or vendor termination). ²

Deliverable: a one-page “Shared/Group Account Restrictions Standard” that your IAM and platform teams can enforce.

Step 2: Inventory all shared and group accounts in scope

You cannot control what you cannot find. Build an inventory using:

• IAM directory exports (naming patterns like “admin”, “shared”, “ops”, “shift”, “svc” are a start, not proof).
• Local accounts on servers and network devices.
• Database accounts, application admin consoles, SaaS “shared admins”.
• Third-party provided credentials.
• “Hidden” shared access via password managers, wiki pages, runbooks, or CI/CD variables.

Output: a single register with fields: system, account name, type (shared/group), privilege level, owner, business justification, last used, authentication method, vault/PAM status, and disposition (keep with controls, convert, retire). ²

Step 3: Triage and disposition

For each identified account, decide:

Decision matrix

• Convert to named accounts when the system supports individual identities. This is the default.
• Keep as shared/group with controls only if it meets your written standard.
• Retire when unused or replaced.
• Temporary exception only with documented rationale, compensating controls where possible, and an end date/exit plan.

Make one person accountable: the system owner signs the justification, Security/IAM signs the control sufficiency. ²

Step 4: Implement enforcement mechanisms

Policy without enforcement fails audits. Common enforcement moves:

• Require shared credentials to live only in a controlled vault/PAM; block human knowledge of the raw password.
• Disable direct login where feasible; require access through a broker (PAM proxy, bastion, SSO, privileged session gateway).
• Enforce MFA and conditional access on any workflow that results in shared access.
• Set automated rotation for shared credentials, especially after checkout or personnel change.
• Add detection: alerts for interactive logons by shared accounts, logons outside expected networks, and privilege escalation events. ²

Step 5: Build the recurring control operation (review + evidence)

Run a repeatable review that answers:

• Which shared/group accounts exist today?
• For each, do we still have a valid justification?
• Do logs prove individual attribution for each use?
• Did we remove/convert/rotate as required?

A practical cadence is: review high-risk systems more often and lower-risk systems on a slower cycle. Your standard should state the cadence so audit expectations match your design. ²

Step 6: Make exceptions survivable

Define an exception process with:

• documented constraint (why named accounts are not possible),
• compensating controls in place now,
• remediation plan (who, what, dependency),
• reapproval requirement,
• termination condition (system upgrade, contract end, platform replacement). ²

Required evidence and artifacts to retain

Keep evidence that proves both design and operation:

1. Control card / runbook
   • Objective, owner, scope, triggers, steps, exception rules.
2. Shared/group account restrictions standard
   • Your organization-defined parameters in writing. ¹
3. Current inventory (register)
   • Exported list plus governance fields (owner, justification, disposition).
4. Approvals
   • System owner + security/IAM approvals for each retained shared/group account.
5. Technical configuration evidence
   • Vault/PAM configuration screenshots or exports, MFA enforcement, conditional access rules, password rotation settings.
6. Usage attribution evidence
   • PAM checkout logs mapped to individuals, session logs/recordings references, ticket IDs tied to access events.
7. Periodic review package
   • Meeting notes or sign-off, exceptions list, remediation tickets, closure proof.

If you use Daydream to manage requirement-level controls, store the control card, inventory evidence, and review packets in one place so you can answer diligence questions without assembling artifacts manually.

Common exam/audit questions and hangups

Auditors and assessors tend to drill on these points:

• “Show me all shared and group accounts.” They expect completeness, not a best-effort list.
• “What are your explicit criteria for allowing them?” If criteria are vague, the control fails AC-2(9). ¹
• “How do you attribute activity to an individual?” Shared password knowledge is a red flag.
• “Who approves, and how do you revalidate?” One-time approvals do not prove ongoing compliance.
• “How do you handle third-party support?” They will test whether third parties get named access, brokered access, or uncontrolled shared credentials.

Hangup to anticipate: teams confuse service accounts with shared/group human accounts. Service accounts still need controls, but AC-2(9) is specifically about accounts used by multiple people.

Frequent implementation mistakes (and how to avoid them)

1. Mistake: Defining restrictions too broadly

   • “Shared accounts allowed where necessary” is not an enforceable parameter.
   • Fix: enumerate allowed scenarios and required controls with pass/fail checks. ²

2. Mistake: Keeping shared admin credentials in runbooks or chat

   • Fix: move to vault/PAM, restrict visibility, require individual checkout identity.

3. Mistake: Inventory is directory-only

   • Fix: include local accounts, SaaS admin consoles, network devices, and third-party provided credentials.

4. Mistake: No proof of individual attribution

   • Fix: require checkout logs and session logs; tie each use to a ticket.

5. Mistake: Exceptions become permanent

   • Fix: enforce reapproval and a remediation plan with a clear termination condition.

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement, so this page does not list specific cases.

Risk still maps cleanly to outcomes: shared/group accounts weaken non-repudiation, slow investigations, and increase the blast radius of credential compromise. In regulated environments, those risks become audit findings because they directly impair your ability to demonstrate controlled access and accountable administration under NIST-aligned assessments. ²

Practical 30/60/90-day execution plan

First 30 days (Immediate)

• Assign an owner (IAM or Security) and publish the AC-2(9) control card.
• Draft and approve the shared/group account restrictions standard (your ODP). ¹
• Start the inventory: pull directory exports, platform lists, and known shared admin paths.
• Freeze new shared accounts: require security approval for any creation until the standard is live.

Days 31–60 (Near-term)

• Complete inventory and classify accounts by privilege and system sensitivity.
• Convert easy wins to named accounts (systems with SSO or directory auth).
• Put remaining shared/group accounts into vault/PAM and enforce MFA at the access path.
• Implement ticket linkage and logging requirements for each use.

Days 61–90 (Operationalize)

• Run the first formal revalidation review and produce a review packet (inventory, approvals, exceptions, remediation status).
• Close or document exceptions with remediation plans.
• Add monitoring alerts for interactive logins by shared accounts and out-of-policy usage.
• Establish steady-state cadence and assign recurring tasks in your GRC system (Daydream or equivalent) so evidence is captured every cycle.

Frequently Asked Questions

Are shared accounts completely prohibited under AC-2(9)?

No. AC-2(9) allows shared and group accounts only if they meet your organization-defined restrictions. Your job is to define those restrictions clearly and enforce them. ¹

What’s the difference between a shared account and a service account for this control?

A shared account is typically a human-operated credential used by multiple people. A service account is intended for a system or application process; it can still be risky, but AC-2(9) focuses on shared/group human use and the accountability gap.

How do we prove accountability if we must keep a shared admin account on a legacy system?

Put the credential in a vault/PAM with individual checkout, require MFA, and retain checkout logs and session logs tied to a ticket. Pair that with documented justification and periodic reapproval. ²

Can a third party use a shared credential if they insist on it?

Treat it as a high-friction exception. Prefer named third-party identities or brokered access; if you cannot, require vault-based checkout with individual attribution and contractually require the third party to follow the workflow.

What evidence do auditors usually ask for first?

They ask for your written restriction criteria, the current inventory of shared/group accounts, and proof that each retained account was approved and is controlled (vaulting/MFA/logging). ²

How do we keep this from turning into a one-time cleanup project?

Add creation gates (no shared/group account without approval) and run recurring reviews that output a consistent evidence packet. Track remediation to closure for any account that drifts out of policy.

Footnotes

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

2. NIST SP 800-53 Rev. 5