IR-4(2): Dynamic Reconfiguration

To meet the ir-4(2): dynamic reconfiguration requirement, you must build incident response actions that can reconfigure systems dynamically during an incident (for defined events and system elements), and you must be able to prove those actions are planned, authorized, tested, and repeatable. Operationally, this means pre-approved “reconfiguration playbooks” that your responders can execute quickly, with logs and approvals captured.

Key takeaways:

• Define which incident types trigger dynamic reconfiguration and which system components can be reconfigured.
• Pre-stage technical mechanisms (network, identity, endpoint, cloud controls) so responders can act within incident workflows.
• Retain evidence that reconfiguration actions are planned, governed, tested, and executed with traceable records.

IR-4(2) is an enhancement to NIST SP 800-53’s incident response capabilities. It pushes teams past “investigate and eradicate” into “change the system behavior while the incident is unfolding.” That can mean isolating a subnet, rotating credentials, switching traffic flows, forcing step-up authentication, disabling risky integrations, or temporarily tightening egress rules. The point is speed with control: you want actions that are fast enough to blunt attacker movement, but governed enough to avoid taking the business down or destroying evidence.

For a Compliance Officer, CCO, or GRC lead, the fastest path to operationalizing IR-4(2) is to treat dynamic reconfiguration as a small set of pre-authorized incident actions tied to clear triggers, bounded scope, and logged execution. Your goal is to make reconfiguration “ready to run” under pressure, not a bespoke engineering project during a breach.

This page translates the control text into implementable requirements, defines ownership boundaries, and lists the artifacts auditors ask for. Citations reference the NIST SP 800-53 Rev. 5 catalog and overview materials ¹.

Regulatory text

NIST SP 800-53 IR-4(2): Dynamic Reconfiguration states:
“Include the following types of dynamic reconfiguration for {{ insert: param, ir-04.02_odp.02 }} as part of the incident response capability: {{ insert: param, ir-04.02_odp.01 }}.” ¹

What the operator must do with this text

The placeholders indicate this control is organization-defined in two key ways:

1. You define what events/scope require dynamic reconfiguration (the “for …” parameter).
2. You define which types of dynamic reconfiguration you will perform (the “include the following types …” parameter).

Practically, you must (a) choose the reconfiguration actions that matter in your environment, (b) embed them into incident response procedures, and (c) demonstrate the organization can execute them under controlled conditions with traceability.

Plain-English interpretation

Dynamic reconfiguration means you can change the live security posture of systems during an incident through planned, repeatable changes, rather than waiting for maintenance windows or ad hoc engineering. IR-4(2) expects you to decide in advance which “knobs” responders can turn and under what conditions.

Examples of “knobs” (choose what fits your architecture):

• Network containment: quarantine a host/VLAN, block east-west routes, tighten egress.
• Identity containment: disable accounts, revoke sessions/tokens, rotate secrets, force password reset, enforce MFA.
• Workload containment (cloud/on-prem): cordon nodes, scale down exposed services, disable public endpoints, rotate keys, restrict security groups.
• Endpoint response: isolate device from network, kill processes, block hashes, enforce application control rules.
• Monitoring posture: increase logging levels, enable packet capture on a segment, route more telemetry to SIEM.

The compliance test is simple: can you show that dynamic reconfiguration is part of IR, not an improvised reaction?

Who it applies to

Entity scope (typical):

• Federal information systems and contractor systems that handle federal data and are assessed against NIST SP 800-53 ².

Operational context (where this becomes real):

• Environments with centralized control planes (cloud, SDN, EDR, IAM) where changes can be executed quickly.
• High-availability systems where “just shut it down” is not acceptable.
• Organizations with third-party dependencies (SaaS, MSP, incident response retainer) where reconfiguration rights and workflows must be contractually and operationally clear.

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

Step 1: Define the “ODP” decisions (your organization-defined parameters)

Create a short IR-4(2) definition memo or control statement that answers:

• Triggering incidents: Which incident categories require dynamic reconfiguration? (Example: suspected credential compromise, lateral movement, data exfiltration indicators, malware outbreak.)
• In-scope assets: Which environments are covered? (Example: production cloud accounts, corporate endpoints, identity provider, core network.)
• Approved actions: The specific reconfiguration actions responders may take.
• Boundaries: What is explicitly out of scope (e.g., actions that would erase forensic evidence, or actions requiring CAB unless life safety is involved).

Deliverable: a one-page “IR-4(2) parameters” document mapped into your IR plan.

Step 2: Build reconfiguration playbooks that map to your IR lifecycle

For each approved action, document:

• Purpose (what threat it mitigates)
• Preconditions (signals that justify action)
• Execution steps (tool-specific commands/workflows)
• Roles and approvals (who can execute, who must approve, who is informed)
• Backout steps (how to restore safely)
• Evidence capture (what screenshots/log exports/tickets must be saved)

Keep the playbooks short. Most teams fail here by writing a policy paragraph instead of executable steps.

Step 3: Pre-stage permissions and tooling (the part auditors probe)

Dynamic actions require rights. Set up:

• Break-glass roles with strong authentication and tight logging.
• Just-in-time access for responders where feasible.
• API/service accounts for automation with scoped permissions.
• Tool coverage: EDR isolation, firewall/SG changes, IdP session revocation, secrets rotation, WAF rules, DNS changes, email controls.

Control objective: responders can execute the playbooks without waiting on ad hoc admin access.

Step 4: Embed into incident command and change governance

You need a “fast path” that still respects governance:

• Define an incident emergency change procedure (who can approve rapidly; what gets documented afterward).
• Ensure actions route through an incident ticket or case management system.
• Require a post-action review for high-impact reconfiguration (customer impact, production outages, broad access revocations).

A common compromise that works: pre-approve a narrow set of actions (quarantine, token revocation, block egress) and require explicit incident commander approval for anything that changes customer-facing availability.

Step 5: Test it and record results

Run tabletop exercises and, when feasible, controlled technical tests:

• Validate the action works (quarantine actually isolates; token revocation actually forces re-auth).
• Validate logging and evidence capture.
• Validate communications (SOC, SRE, Legal/Privacy, third parties).

You do not need perfect automation. You need repeatable execution and proof.

Step 6: Operationalize recurring evidence collection

Make evidence collection routine:

• Monthly/quarterly export of samples of incidents where dynamic actions were executed (or tests if no incidents).
• Access reviews for break-glass and IR roles.
• Tool configuration baselines for key reconfiguration mechanisms.

Daydream note (earned mention): Daydream can help you map IR-4(2) to a named control owner, a single implementation procedure, and a recurring evidence checklist so you do not rebuild the same audit packet each cycle.

Required evidence and artifacts to retain

Keep artifacts tied to design, readiness, and execution:

Design / governance

• IR plan section referencing dynamic reconfiguration (IR-4(2)) ³.
• IR-4(2) organization-defined parameters memo (triggers, scope, action types).
• Role/RACI: incident commander, SOC, IAM, NetOps/SRE, approvals.

Technical readiness

• List of tools and control points used for reconfiguration (EDR, IdP, firewall/WAF, cloud security groups, PAM).
• Access control configuration for IR responders (break-glass design, JIT workflows, logging settings).
• Change governance procedure for emergency incident changes.

Execution proof

• Incident tickets/case records showing: trigger, approval, action taken, timestamps, affected assets.
• System logs: IAM audit logs, firewall rule change logs, EDR action logs, cloud control-plane audit logs.
• Post-incident review documenting what was changed and whether backout occurred.

Common exam/audit questions and hangups

Auditors usually press on these points:

1. “What counts as dynamic reconfiguration here?”
   Show your defined list of actions and where they live in IR procedures.

2. “Who can do it, and how is it controlled?”
   Provide RBAC/break-glass/JIT evidence plus logs showing actions are attributable.

3. “Prove you can execute during an incident.”
   Provide incident samples or test records with timestamps and tool logs.

4. “How do you avoid causing outages or destroying evidence?”
   Show preconditions, approval gates, backout steps, and forensic considerations in playbooks.

Frequent implementation mistakes (and how to avoid them)

Mistake	Why it fails	Fix
Writing a policy statement with no executable actions	Auditors can’t see capability	Create playbooks with click-by-click or command-by-command steps
No clear triggers	Teams overuse or underuse reconfiguration	Define “when to use” criteria tied to detection signals
Responders lack access	Actions happen too late	Pre-stage JIT/break-glass access with logging
Overbroad actions (e.g., “shut down prod”)	Business impact becomes the story	Start with narrow containment actions; expand after testing
No evidence packet	Control “exists” only in people’s heads	Standardize what logs/screenshots/tickets must be retained

Risk implications (why auditors care)

IR-4(2) reduces dwell time and limits blast radius by enabling containment actions while investigation continues. If you cannot reconfigure dynamically, you may be forced into slower changes, larger outages, or extended attacker movement. The control also protects governance: dynamic does not mean uncontrolled; it means preplanned actions executed with traceability ².

Practical 30/60/90-day execution plan

First 30 days (Immediate)

• Assign a single control owner (often Head of IR/SOC manager) and name technical co-owners (IAM, Network, Cloud/SRE).
• Draft IR-4(2) organization-defined parameters: triggers, scope, allowed action types.
• Inventory current reconfiguration control points: IdP, EDR, firewall/WAF, cloud security, PAM.

By 60 days (Near-term)

• Publish playbooks for the top reconfiguration actions your team can execute now (focus on identity + endpoint + network).
• Implement/validate break-glass or JIT access and confirm all actions produce audit logs.
• Run a tabletop that includes a decision to execute at least one reconfiguration action; capture artifacts as if for an audit.

By 90 days (Operational)

• Run a controlled technical exercise (in a test environment where possible) to execute actions end-to-end and verify telemetry.
• Standardize evidence capture: incident ticket templates, log export steps, and a storage location with retention.
• Add IR-4(2) checks into recurring IR readiness reviews (access review, playbook review, tool health checks).

Frequently Asked Questions

What qualifies as “dynamic reconfiguration” for IR-4(2)?

A planned, rapid change to system configuration or security posture taken during an incident to contain or reduce impact. The control expects you to define which actions count in your environment and include them in IR procedures ³.

Do we need full automation to satisfy IR-4(2)?

No. You need a demonstrable capability: documented actions, controlled permissions, and repeatable execution with logs. Automation helps, but auditors usually accept well-governed manual execution if it is fast and traceable.

How do we handle approvals without slowing responders down?

Pre-approve a narrow set of high-value, low-regret actions and route them through an incident “emergency change” path. Put the approval step inside the incident ticket so it is recorded and time-stamped.

What evidence is strongest for auditors?

Incident records showing the decision, approval, and action taken, plus tool logs from the control plane (IdP, EDR, firewall, cloud audit logs). A test record is acceptable when there have been no real incidents, but it should show the same logging and governance artifacts.

How does IR-4(2) relate to third parties like an MSSP or cloud provider?

If a third party performs reconfiguration, your contract and runbooks must define who can take which actions, how you approve them, and how you receive logs and timestamps afterward. Treat third-party actions as part of your incident evidence set.

We worry dynamic changes will destroy forensic evidence. What’s the right balance?

Build playbooks that separate containment from cleanup and specify evidence capture steps before high-impact actions. For example, isolate a host first, then collect volatile data, then reimage, with approvals and logs at each step.

Footnotes

1. NIST SP 800-53 Rev. 5 OSCAL JSON; Source: NIST SP 800-53 Rev. 5

2. NIST SP 800-53 Rev. 5; Source: NIST SP 800-53 Rev. 5 OSCAL JSON

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