SC-37: Out-of-band Channels

To meet the sc-37: out-of-band channels requirement, you must define specific “out-of-band” methods (separate from the primary network path) and use them to deliver or transmit designated sensitive items between defined parties. Operationalize SC-37 by selecting approved channels, documenting when they are required, training operators, and retaining evidence that the alternate path was used.

Key takeaways:

• SC-37 is a design-and-procedure control: you must predefine which information uses out-of-band delivery and which channels are approved.
• “Out-of-band” means a separate channel from the main communications path, reducing interception and manipulation risk.
• Auditors will look for repeatable triggers, proof of use, and ownership, not a one-time policy statement.

SC-37 (Out-of-band Channels) is easy to misunderstand because it sounds like a technical encryption control. It is not. SC-37 is about separating the path used to deliver or transmit certain sensitive information or material from the primary communications channel, so a compromise of the main channel is less likely to compromise the protected item. The control text is parameterized, meaning your organization must define: (1) what is protected (the item being delivered/transmitted), (2) who it is sent between, and (3) which out-of-band channels are approved for that purpose. ¹

For a Compliance Officer, CCO, or GRC lead, the fastest way to operationalize SC-37 is to treat it like a tightly-scoped requirement with clear triggers. You want a short list of high-risk “objects” (for example, recovery secrets, root credentials, cryptographic key material, break-glass procedures, or sensitive configuration files) and a small set of approved alternate channels (for example, courier delivery, a dedicated secure file transfer mechanism, or a separate authenticated messaging workflow). Your goal is consistency: operators should know exactly when to switch channels, and you should be able to prove it during assessment. ²

Regulatory text

Control requirement (excerpt): “Employ the following out-of-band channels for the physical delivery or electronic transmission of [defined items] to [defined parties]: [defined channels].” ¹

What the operator must do:

1. Define the protected item(s) that require out-of-band delivery/transmission (the thing that must travel).
2. Define sender/recipient scope (who can send and who can receive; internal teams, admins, third parties, or system components).
3. Define the approved out-of-band channel(s) (how it can be delivered/transmitted outside the primary channel).
4. Ensure actual use of those channels whenever the trigger condition occurs, and keep evidence that the organization followed its own defined method. ¹

Plain-English interpretation (what SC-37 really means)

SC-37 requires you to move certain sensitive information using an alternate path so that an attacker who compromises your main email, ticketing system, chat tool, network link, or application channel cannot automatically intercept or modify the item. Out-of-band is about path separation and procedural discipline.

Common “SC-37 moments” in real operations:

• Sharing break-glass credentials or recovery codes during an incident.
• Delivering cryptographic key material or key-encryption keys to a platform team.
• Sending network device configs or firewall rule sets to an implementation partner.
• Providing privileged access onboarding details to a third party.

If the same compromised channel can carry both the instruction and the secret (or both the request and the approval token), you likely need an out-of-band step.

Who it applies to (entity and operational context)

SC-37 is relevant when you operate under NIST SP 800-53 (directly or via inherited requirements), including:

• Federal information systems and programs. ²
• Contractor systems handling federal data, including cloud and managed services environments where sensitive administrative material or security artifacts are exchanged. ¹

Operationally, SC-37 applies wherever you have:

• Privileged administration and SRE operations
• Key management and certificate operations
• Incident response and disaster recovery
• Third-party access management and secure onboarding/offboarding
• Change management for sensitive network/security configurations

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

1) Set scope: define “what must be out-of-band”

Create a short register of SC-37-protected objects. Keep it small enough that teams will follow it. Examples you may include (choose what fits your environment):

• Root/admin credentials, break-glass accounts, recovery codes
• Private keys, seed material, HSM initialization material
• One-time approval tokens for high-risk changes
• Sensitive configuration exports (IAM policies, firewall configs)

Output: “SC-37 Protected Items List” with clear definitions and examples.

2) Define the “to/from” boundaries

The requirement expects you to define transmission/delivery to whom the protected items may be sent. Make it operational:

• Internal roles/teams (e.g., Security Operations, IAM Engineering)
• Named functions for recipients at third parties (e.g., “Customer’s Security Admin role”, “MSP Primary Engineer”)
• System-to-system boundaries if applicable (e.g., “IdP to PAM vault”)

Output: “Authorized Senders/Recipients Matrix” tied to roles, not person names.

3) Approve specific out-of-band channels (and ban the rest)

Pick channels that are: separable from the primary channel, authenticated, and support logging. Typical patterns:

• Physical delivery: couriered sealed envelope, tamper-evident packaging, in-person handoff with ID verification.
• Electronic out-of-band: a separate secure channel with independent authentication (for example, a dedicated secure transfer workflow or a distinct system used only for secrets exchange).

Define:

• Allowed channels by object type (some items may require physical delivery)
• Minimum security properties (authentication, encryption, access control, retention)
• Who can initiate transmission, who approves, and how to confirm receipt

Output: “SC-37 Approved Channel Standard” plus a short prohibited list (e.g., “no email for recovery codes”).

4) Embed SC-37 into workflows (so it happens by default)

Map SC-37 triggers into operational processes:

• Incident response runbooks: “If requesting break-glass credentials, use Channel X; confirm identity via Method Y.”
• Change management: “If pushing sensitive security configs to a third party, transfer via approved out-of-band method.”
• Access requests: “If providing initial privileged onboarding secret, deliver via out-of-band method, then force rotation at first use.”

Output: Updated runbooks, ticket templates, and SOPs with explicit SC-37 steps.

5) Assign ownership and set review cadence

SC-37 fails in audits when nobody “owns” the channel list and triggers. Assign:

• Control owner (often Security, IAM, or GRC)
• Implementers (Service Desk, SRE, Incident Commanders)
• A routine review of protected items/channels when tools or third parties change

Output: Control ownership record and a lightweight review procedure. This aligns with the recommended practice to map SC-37 to owners, procedures, and recurring evidence. ¹

6) Prove operation: logging and evidence capture

Build evidence capture into the workflow so operators don’t have to remember it. Options:

• Ticket fields: “SC-37 invoked? yes/no”, “Channel used”, “Approver”, “Receipt confirmed”
• System logs: secure transfer audit logs, vault access logs, courier receipts
• Message templates: standardized confirmations and identity verification steps

Output: An evidence pack you can pull per event and per period.

Required evidence and artifacts to retain

Auditors typically expect artifacts that show SC-37 is defined and used consistently. Maintain:

• SC-37 control narrative (what items, what recipients, what channels)
• Protected Items List and Authorized Senders/Recipients Matrix
• Approved Channel Standard (technical and procedural requirements)
• Runbooks/SOP excerpts showing SC-37 triggers embedded in processes
• Sample transactions: redacted tickets, transfer logs, chain-of-custody records, approvals, receipt acknowledgements
• Training/awareness records for staff who handle protected items

If you use Daydream to manage control mapping and evidence requests, treat SC-37 as a recurring evidence control: assign owners, define the artifact list, and schedule periodic evidence pulls so assessment prep is not a scramble.

Common exam/audit questions and hangups

Expect assessors to ask:

• “What information is covered by SC-37 in your environment, and where is that defined?” ¹
• “Show examples where you used the out-of-band channel for a real event.”
• “How do you ensure staff don’t send secrets over email/chat during incidents?”
• “What makes this channel ‘out-of-band’ relative to the primary channel?”
• “How do you confirm recipient identity and receipt?”

Hangups that slow teams down:

• Treating SC-37 as “we have encryption,” instead of “we use a separate channel for specific objects.”
• Defining too many protected items, so operators ignore the rule.
• Having an approved channel but no logs or proof that it was used.

Frequent implementation mistakes and how to avoid them

1. Mistake: Out-of-band defined as a second message in the same tool (e.g., “send password in a separate email”).

   • Fix: Out-of-band should have meaningful separation (different system, different authentication path, or physical delivery) and should be explicitly defined in your standard.

2. Mistake: No defined triggers (“Use out-of-band for sensitive data” with no list).

   • Fix: Maintain a protected items list with concrete examples tied to workflows. ¹

3. Mistake: Third-party exchanges are excluded (people focus only on internal admin teams).

   • Fix: Include third-party onboarding/offboarding and support escalation processes where secrets/configs get exchanged.

4. Mistake: Evidence is improvised after the fact

   • Fix: Add required fields to tickets and require audit logs from the selected channel.

Risk implications (why assessors care)

SC-37 reduces the chance that a compromise of a primary channel (email compromise, ticketing compromise, chat compromise, or man-in-the-middle on a main link) leads directly to compromise of your highest-impact secrets and administrative pathways. Control failure increases the probability of:

• Privilege escalation through intercepted admin credentials
• Unauthorized changes through stolen one-time approval artifacts
• Key compromise that expands the blast radius beyond a single system

This is why SC-37 is assessed as an operational discipline problem as much as a technical one. ²

Practical 30/60/90-day execution plan

First 30 days (foundation and scoping)

• Name a control owner and implementation owners (Security/IAM/IT Ops).
• Draft the Protected Items List and Authorized Senders/Recipients Matrix.
• Select approved out-of-band channels and document minimum requirements.
• Update one high-risk runbook (incident break-glass is a common starting point).

Days 31–60 (workflow integration and training)

• Add SC-37 prompts and required fields to ticket templates and IR checklists.
• Train operators who will execute the control under pressure (IR leads, service desk, IAM).
• Run a tabletop: simulate a break-glass event and capture the evidence you expect to produce.

Days 61–90 (evidence hardening and assessment readiness)

• Collect a small set of real examples (redacted) and store them in your audit repository.
• Validate logging/audit trails for the chosen channels.
• Tighten exceptions: define who can approve, when exceptions are allowed, and what compensating steps apply.
• In Daydream, map SC-37 to the owner, procedure, and recurring evidence artifacts so evidence collection becomes routine. ¹

Frequently Asked Questions

What qualifies as an “out-of-band channel” for SC-37?

SC-37 expects a channel that is meaningfully separate from the primary communication path used for the main transaction. Define this explicitly in your standard so teams don’t treat “a second email” as compliant. ¹

Do we need SC-37 if we already encrypt email and files?

Encryption helps confidentiality in transit, but SC-37 focuses on reducing dependency on a single channel. If your main channel is compromised, an out-of-band method can still protect the protected item.

Which information should we put on the SC-37 protected list first?

Start with the items that enable privileged access or irreversible security impact, such as break-glass credentials, recovery codes, and key material. Keep the list short so it stays executable under incident conditions.

How do we handle third parties who insist on receiving secrets in email or tickets?

Treat it as a contract and process requirement: define allowed channels for third-party exchanges and route secrets through your approved out-of-band method. If you allow exceptions, require documented approval and immediate rotation after receipt.

What evidence will an assessor ask for?

Expect requests for the defined protected items, approved channels, roles authorized to send/receive, and real examples showing the out-of-band channel was used with approvals and receipt confirmation. ¹

How do we keep SC-37 from slowing down incident response?

Pre-stage the workflow in runbooks and ticket templates, and make the out-of-band channel easy to access for authorized responders. Test the process in tabletop exercises so teams can execute without improvising.

Footnotes

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

2. NIST SP 800-53 Rev. 5