What MP-4 media storage requires and where teams get stuck
MP-4 Media storage asks an organization to define the types of digital and non-digital media it holds, physically control and store that media within defined controlled areas, and protect it until the media are destroyed or sanitized with approved equipment, techniques and procedures. If you run a system in the moderate or high baseline, MP-4 is one of the controls an assessor will ask you to evidence. It is not allocated to the low baseline or to the privacy baseline, so a low-impact system does not need it, though the organization may still choose to apply it. The risk it addresses is simple: media left unattended, unlabeled or outside any defined boundary can be copied, lost or stolen long before anyone decides it should be destroyed. Under SP 800-53B, MP-4 is selected for the moderate and high baselines, and the catalog lists 14 related controls, including MP-2, MP-7 and PE-3, which you should review alongside it.
SP 800-53A Rev. 5 assesses MP-4 through 5 determination statements. An assessor will examine the system media protection policy, the procedures that address media storage, the access control policy and procedures, and the system media and designated controlled areas themselves. They will interview the personnel who hold media protection and storage responsibilities, and they will test the organizational processes for storing media and the mechanisms that enforce secure storage. The hardest work usually happens before any of that. Teams must first decide which media types are in scope, such as backup tapes, removable drives, printed reports and archived optical discs, and then name the physical spaces that count as controlled areas. Many organizations have never written either list. Confirm with your assessor which media types they expect you to define, and build an inventory that records each item, its location, its custodian and its destruction or sanitization status.
Once the definitions exist, evidence should show that storage actually matches them. Expect to produce the inventory, the access list for each controlled area, locked storage records, and sanitization or destruction certificates that close out each item's life. For digital backup media, an assessor may ask how you know stored copies have not been altered. Tools such as Bareos keep a catalog of backed-up files and manage verify jobs, while restic's restic check --read-data reads pack files back to confirm stored data is unmodified. Those outputs support the storage claim but do not replace the physical controls. Ask your team to confirm how each tool records its results and retention, and whether your organization has a documented owner for the inventory.
Which media, areas and systems fall under MP-4 scope
MP-4 applies only to the media, areas and systems the organization defines, so these definitions come first and belong to the organization, not to an assessor or a consultant. Each decision below changes which storage locations must be controlled, inventoried and protected until sanitization or destruction.
Defined media types
Decide which media types count for MP-4, for example server disks, backup tapes, removable drives, optical discs and paper records. The control only reaches media the organization has defined, so an undefined category is an unprotected category in an assessment. Record each type in the inventory with its owner, location and the system it supports. Ask the assessor to confirm the list matches what the system security plan describes.
Controlled storage areas
Define which rooms, cabinets, racks and vaults are controlled areas for media storage, and document how access to each is limited and monitored. Locked storage, badge logs and visitor records are the usual evidence. Paper records and spare drives kept at desks often fall outside the defined area, so check them during scoping rather than during the assessment.
Backup media and offsite copies
Backup tapes, replicated disks and offsite vaults hold the same data as production systems and are frequently forgotten in media inventories. Include every location where a backup copy sits, including courier bags and retention rooms. Confirm that the backup platform's catalog can identify which media hold which datasets, since that link is what makes the inventory useful.
Cloud-hosted storage
Cloud object stores, block volumes and snapshots are storage media for MP-4 purposes, even though no one touches a physical device. The organization still defines what counts as controlled, usually through account boundaries, encryption key ownership and access policies. Confirm with the cloud provider which physical controls it inherits and which the organization must evidence itself.
Third-party storage providers
Offsite vault operators, shredding services, colocation facilities and managed backup providers hold media on the organization's behalf. Decide which of their storage obligations the organization accepts through contract and which it verifies directly. Request the provider's storage procedures, access logs and inventory reports, and confirm how they are reviewed before they are relied on as evidence.
Systems that write to media
Identify which applications, backup jobs and export processes write data to removable or offsite media, because each one creates a copy that MP-4 may cover. Document the systems in the system boundary and note any that bypass the defined storage process. Ask the assessor to confirm how these systems are included in the scope statement.
How an assessor tests MP-4 storage
This table maps the five SP 800-53A determination statements for MP-4 to the assessment method, the objects an assessor examines, interviews or tests, the evidence to prepare and the findings that commonly stall an assessment. Read each row as a question the assessor will ask and the proof the organization should have ready before fieldwork begins.
| Assessment focus | What the assessor examines, interviews or tests | Evidence to prepare | Common findings |
|---|---|---|---|
| Media protection policy and storage procedures | Examine the system media protection policy and procedures addressing media storage, checking that they define storage requirements for each media type in scope | Approved MP policy with owner and review date, storage procedure naming defined media types, approval records | Policy exists but does not name the media types it governs, or procedures are generic and not tied to the system |
| Access control policy as applied to stored media | Examine the access control policy and procedures to confirm they restrict who can reach stored media and how that access is granted and removed | Access control policy sections covering storage areas, access lists for controlled areas, recent access review records | Access rules cover systems but not physical or offline media such as tapes, drives or paper records |
| Designated controlled areas and stored media | Examine the system media and the designated controlled areas where media are kept, comparing the physical locations against what the documentation describes | Current media inventory with storage location, controlled area map, lock and access configuration records, photographs or site walkthrough notes | Controlled areas are named in policy but not verified on site, or inventories omit media held in offices or off-site storage |
| Personnel with storage responsibilities | Interview personnel with system media protection and storage responsibilities to confirm they know the storage rules, their duties and how exceptions are handled | Role assignments, training or briefing records, signed acknowledgments, contact list for custodians | Staff describe informal practices that differ from the written procedure, or the named custodian has changed without an update |
| Storage processes and mechanisms | Test the organizational processes for storing information media and the mechanisms that implement secure storage, such as locks, cabinets, logged key control and media check-in and check-out | Test results or walkthrough records showing media are stored as documented, sample tracing from inventory to location, key or combination custody logs, storage mechanism configuration | Storage mechanisms are present but not used consistently, media are left unattended, or the process ends at sanitization or destruction without a protected interval before it |
Implementing MP-4 in five steps
This sequence turns the MP-4 requirement into a working storage practice: defined media types, controlled areas, a reconciled inventory, protected storage and a documented holding period that runs until sanitization or destruction. Each step leaves a record an assessor can examine.
Define media types and controlled areas
The organization decides which media types fall under MP-4, such as backup tapes, removable drives, optical discs, printed records and retired disks awaiting sanitization. It also names the physical areas where that media may be stored. The policy owner, usually the security or records function with facilities input, approves the list. Done means a written media type register and a list of controlled areas, each with an accountable owner, are approved and tied to the media protection policy from MP-1.
Build and reconcile the media inventory
Staff record every item of defined media with an identifier, media type, information category, location, custodian and status such as in use, in storage or awaiting sanitization. For digital media stored on systems, backup catalogs such as those kept by Bareos can help locate tape and volume records. A physical count is then reconciled against the inventory. Done means the inventory matches the physical count, and every discrepancy has a recorded explanation and an owner.
Set locked storage and restricted access
Facilities staff provide locked cabinets, safes or rooms inside the controlled areas, and the access list for each container is limited to roles that MP-2 authorizes. Keys, combinations and badge rights are issued and logged. Environmental conditions such as temperature, humidity and fire exposure are checked against the media manufacturer's guidance, which the organization should confirm for each media type. Done means the storage locations, access lists and environmental checks are documented and a sample test confirms that unauthorized staff cannot open the containers.
Protect encrypted digital media and backups
For digital media that holds sensitive information, the team confirms that encryption keys are stored apart from the media and that restore tests run against the stored copies. Encrypted backup repositories can be verified with restic's check command, using --read-data or --read-data-subset to read pack files back, and key material can be managed in a self-hosted secrets service such as OpenBao. Done means a verification record shows the stored copies are readable and unmodified, and key custody is documented.
Document the holding period and sanitization handoff
For each media type, the organization records how long media stays in storage, who approves release from storage, and how media moves to sanitization or destruction under MP-6. Media awaiting sanitization stays in the controlled area with its inventory status updated. The sanitization record then closes the inventory entry. The organization sets these rules itself; no fixed retention period is implied here. Done means each item has a traceable path from storage to a sanitization or destruction record, and the holding rules are approved.
Set a review cadence and retain evidence
The owner sets how often the inventory is reconciled, how often access lists and locks are reviewed, and when the register of media types is revisited after a change in systems or facilities. Each review produces a dated record that assessors can examine. Done means the review schedule is approved, the first review cycle is recorded, and the evidence set (register, inventory reconciliations, access lists, environmental checks and handoff records) is stored where an assessor can reach it.
Protecting media in controlled areas versus cloud and encrypted storage
MP-4 asks the organization to define which types of non-digital and portable digital media must be physically controlled and stored in defined controlled areas, and to protect them until they are destroyed or sanitized. For on-premises sites, an assessor usually starts with the media protection policy, the storage procedures and the designated controlled areas, then walks the room to see whether the stated rules match what happens. The evidence is less about the technology and more about whether the organization can show what is stored, where, and who can reach it.
- Defined media types: A list of the tape libraries, removable drives, optical discs, printed sensitive records and similar items that fall inside the control's scope.
- Controlled area boundaries: Floor plans or site documents that name each storage room, cabinet or safe, and the physical controls that protect it.
- Inventory records: A current register showing item identifiers, location, custodian and the date of last movement or check.
- Access to storage: Lock logs, key or badge records and access lists for each controlled area, reviewed on a stated schedule.
- Disposal hand-off: Records that media stays in controlled storage until it is destroyed or sanitized under MP-6.
Confirm with your facilities and security teams which physical controls already exist, which are new, and who signs off on the inventory before any assessor visit.
Digital media on self-hosted systems, such as backup repositories, file platforms and secrets-backed data stores, still falls under MP-4 when the organization defines it as media. Encryption at rest does not replace the storage requirement, but it changes what the organization can show about protection until destruction. Key custody is the central question: if the same administrators control the data and the keys, the protection is weaker than the configuration suggests, and an assessor will ask who can read the keys and how that access is logged.
- Server-side encryption scope: Nextcloud server-side encryption protects file contents at rest on local and external storage, with keys kept on the server. It does not encrypt file names or folder structure, so the evidence must address that metadata separately.
- Key custody model: Document who can administer the server that holds the keys, and whether any party outside the platform team can recover them.
- Transit-style key management: The OpenBao transit secrets engine encrypts and decrypts application data without storing it, and supports versioned keys with key rotation. Rotation records become part of the storage evidence.
- Backup repository integrity: Bareos keeps a SQL catalog of backed-up files, and restic
checkwith--read-datacan read pack files back to confirm stored data is unmodified. - Scope statement: A written boundary that says which digital stores count as defined media and which are treated as systems under other controls.
Confirm with each platform owner which encryption, key and integrity features are enabled in your configuration, and how each one is evidenced for MP-4.
When data sits with a cloud or hosted provider, MP-4 does not disappear, but the organization must understand which physical controls the provider carries and which remain its own. The organization owns the control, so it needs contractual and technical evidence that the provider's storage meets the defined requirement, along with its own records of what was placed there. Assessors will ask whether the organization can name the storage locations and explain how media are protected until sanitization or destruction.
- Shared responsibility mapping: A table that separates provider-operated physical protection from controls the organization still runs, such as encryption configuration and access reviews.
- Provider evidence: Current third-party reports or attestations the provider publishes, read against the MP-4 requirement, with gaps recorded.
- Data location records: Documented regions, buckets or volumes that hold defined media, kept in the inventory.
- Exit and deletion steps: Procedures for removing data at contract end that tie to the sanitization control.
- Contract clauses: Terms on storage location, subcontractors and notification of changes that the organization can point to during assessment.
Confirm with each provider what it covers, what it excludes, and what documentation it will supply under your agreement.
Evidence that passes an MP-4 assessment
An assessor testing MP-4 looks for a defined set of media types, controlled areas with named access, an inventory that ties each item to a custodian, and records showing that storage is protected until sanitization. The cards below cover the artifacts that connect those points, along with the routine that keeps each one accurate between assessments.
Defined media type list
This is the scope document that states which digital and non-digital media types the organization stores under MP-4, such as backup tapes, removable drives, optical discs and printed records. Assessors compare it against what they find in storage areas, so any media type left off the list is a gap. Review it when new media types enter use, and tie it to the MP-1 policy so the two stay consistent. Confirm the list with the business owners of each information system, not only with the media custodians.
Controlled area register with access lists
The register names each designated controlled area where defined media is stored, the physical or logical boundary around it, and the people authorized to enter. Assessors use it to check that storage locations match the areas the organization declared. Keep the access list current by reconciling it with badge or key issuance and removing departed staff on the same schedule as system account removal. Record the date of each review and who approved it.
Media inventory with custodians
The inventory lists each media item by identifier, type, location, owning system, information category and the named custodian responsible for it. It is the document that proves the organization knows where its media is at any point. Reconcile it against physical counts on a fixed schedule and record discrepancies with their resolution. Stale inventories are a common finding, so tie updates to receiving, transfer and destruction events rather than to the audit calendar.
Storage access logs
Access logs for locked cabinets, vault rooms and controlled storage show who opened storage and when, and they support the claim that media stayed protected while stored. Where media sits in a self-hosted system, such as an encrypted backup repository, the platform's own audit trail can serve the same purpose. Check that logs are retained for the period your policy defines and that someone reviews them, because unreviewed logs show a control that exists on paper only.
Sanitization hand-off records
When media leaves storage for sanitization or destruction, the hand-off record shows the item identifier, the date released, the custodian who released it and the party or process that received it. This record closes the loop between MP-4 storage and MP-6 sanitization, so assessors trace each item from storage to disposal. Confirm that the receiving party or equipment is approved and that certificates of destruction are filed against the inventory entry.
Media storage policy and procedures
The written policy and procedures define how defined media is stored, who is responsible, how access is granted and how storage is protected until sanitization. Assessors examine this document first and then check that staff follow it in practice. Review the document on the cycle set in your MP-1 policy and after any significant change to storage facilities or backup architecture. Staff interviews should match what the document says, so confirm that custodians have read and can explain their duties.
What meeting MP-4 costs in money and effort
This table breaks down the cost components of meeting MP-4 Media storage, who is paid for each, whether it is one-time or recurring, and what drives it up or down. No prices are published here because none were supplied, so use the column on what to request to build a comparable quote. The main takeaway is that most MP-4 cost sits in physical storage and evidence upkeep, while self-hosted open-source tooling mainly removes software license spend.
| Cost component | Who is paid, and for what | One-time or recurring, and main drivers |
|---|---|---|
| Locked storage and controlled area upgrades | Facilities or security contractor for locks, cabinets, cage or room changes; the organization owns the controlled area | Mostly one-time. Drivers: number and type of media, whether a dedicated room is needed, and whether existing space already meets the defined controls |
| Media inventory tooling and process | Internal asset or security staff; implementation partner if a register is built into self-hosted systems | Setup is one-time; upkeep recurs. Drivers: volume of media, how often it moves, and whether the inventory links to sanitization records |
| Engineering time for backup and encryption | Internal platform team or implementation partner for Bareos, restic, Nextcloud server-side encryption and OpenBao key handling | Largely one-time design and deployment, then recurring operations. Drivers: number of systems in scope, key management model, and restore testing frequency |
| Evidence upkeep | Internal compliance or security staff who keep the access logs, storage records, inventory and policy current | Recurring. Drivers: how often assessors sample, change rate of media holdings, and how many locations hold media |
| External testing or review | Independent assessor or consultant for readiness review or control testing; certification bodies or auditors for formal results | Usually periodic. Drivers: scope, number of sites, and whether the assessment uses the examine, interview and test methods of SP 800-53A |
| Auditor sampling and assessment time | Independent assessor or auditor, who samples storage records and observes controlled areas | Recurring with each assessment cycle. Drivers: sample size, number of locations, and quality of evidence ready on arrival |
| Software license spend | Open-source projects are free to license; any commercial support contract is a separate purchase | Self-hosted open source removes most license spend for the tools named here, but support, upgrades and retainers remain costs to confirm |
| What to request in a quote | Ask the provider to itemize each component above with its assumptions, scope and exclusions | Confirm locations, media types and counts, systems in scope, evidence owners, and whether formal assessment fees are included |
Open-source tools that support MP-4 evidence
MP-4 asks for controlled storage and protection of media until sanitization, so assessors look for proof that stored data is inventoried, protected and still intact. The four tools below each produce a different kind of record: backup catalogs, integrity checks, encryption configuration and key lifecycle logs. None of them replaces locked rooms, cabinets or custody procedures, which the organization must still provide and demonstrate.
Bareos backup catalog and restores
Bareos is licensed under AGPL-3.0-only. Its Director schedules and supervises backup, restore, verify and archive jobs, and keeps a SQL catalog of every backed-up file. For MP-4, the catalog is an inventory of what sits on backup media and where it is held, which assessors can compare against the defined media types in your storage procedure. Check that restore tests are recorded, not only backup jobs, because a restore from a chosen date shows the media is readable and complete.
restic integrity checks on stored data
restic is licensed under BSD-2-Clause. Its check command verifies the structural consistency of snapshots, trees and pack files. Adding --read-data or --read-data-subset reads pack files back to confirm the stored backup data is unmodified. Run these checks on a schedule and keep the output, since an unchanged backup on protected media is stronger evidence than a job that reported success. Confirm the frequency and subset size against your own risk decisions, because the tool does not set them.
Nextcloud encryption at rest
Nextcloud is licensed under AGPL-3.0-only. Its server-side encryption protects file contents on local and external storage, with keys kept on the server. It does not encrypt file names or folder structure, so the directory layout remains visible to anyone with raw access to the storage. Record the encryption configuration as evidence, and treat file names as data that still needs physical and access controls. Confirm that encryption is enabled on every storage backend that holds regulated content.
OpenBao transit key rotation
OpenBao is licensed under MPL-2.0. Its transit secrets engine encrypts and decrypts application data without storing that data, and supports versioned encryption keys with key rotation. For stored media, this produces a record of which key version protected which data and when keys were rotated. Keep rotation events, key policies and access logs together so an assessor can trace protection from the key to the stored item. Confirm how key material is backed up and recovered, since losing keys makes encrypted media unreadable.
Who owns MP-4: your team, a partner and the auditor
Your organization owns MP-4. That means it decides which media types are in scope, which spaces count as controlled areas, how storage is protected until media are destroyed or sanitized, and who is accountable when a control fails. The policy and procedures that support MP-4 must be approved by a named owner, and that owner signs off on the system security and privacy plan that describes how the control is implemented. A partner can draft these documents, but the decisions and the signature stay with your staff.
- Define the media and areas: list the digital and non-digital media types the organization stores, and the rooms, cabinets or systems designated as controlled areas.
- Own the policy: approve the media protection policy and the storage procedures, and set the review cycle.
- Accept residual risk: decide which deviations are acceptable and document who approved each one.
- Operate the storage: staff the controlled areas, maintain locks and access lists, and perform periodic inventory checks.
- Sign off evidence: review inventory records and exception logs before they are presented to the assessor.
Check that the named control owner can explain the storage design to an assessor without reading from a vendor document.
An implementation partner prepares the systems and records that MP-4 depends on. Work is usually defined in a written, fixed scope before it starts, and the partner delivers configured systems, documentation and evidence. The partner does not decide the organization's risk acceptance, and it does not certify that the control is met. DeployOpen works in this role: it prepares systems, controls and evidence for an assessment, and it does not issue audit reports, attestations or certifications.
- Build the inventory: set up a media register and asset records that show the item, location, custodian and status.
- Configure storage systems: harden backup repositories and encryption keys so that stored data can be traced and verified. For example, a backup catalog can show which copies exist and when they were last verified (illustrative).
- Prepare procedures: draft storage and inventory procedures for the organization to review and adopt.
- Assemble evidence: collect configuration exports, logs and sample records mapped to the five assessment determination statements.
- Support the assessment: answer technical questions and walk the assessor through systems, without changing evidence after the fact.
Ask the partner to state in writing which deliverables it owns and which decisions remain with you.
The independent assessor examines and tests MP-4 using the procedures in SP 800-53A, which combine examine, interview and test methods. The assessor forms its own conclusions and reports findings. Independence matters because the assessor must not design, implement or operate the controls it tests, and must not sign off the evidence it reviews as if it were the control owner. Where an assessor was also the implementer, the conflict must be disclosed and the work reassessed by a party that is independent.
- Examine documents: read the media protection policy, storage procedures, access control rules and records of controlled areas.
- Interview staff: confirm that personnel with storage responsibilities understand their duties.
- Test the mechanisms: observe locks, inventories and storage processes, and check that they work as documented.
- Issue findings: record each gap, and track whether the organization closes it through a plan of action and milestones.
- Report independently: only the assessor or certification body issues the formal report or certificate.
Before engaging an assessor, confirm its independence rules, the scope of the report and whether it will test your environment or only review documents.
Common MP-4 gaps and how to close them
Most MP-4 findings come from paperwork that does not match the physical or logical reality of media. The gaps below cluster around definitions, inventories, areas and hand-offs, and each has a closing action an assessor can verify. Work through them in order, because the media types and controlled areas you define determine what every other record must cover.
Media types never defined
MP-4 applies to defined types of digital and non-digital media, so an undefined list leaves the assessor with no test scope. Teams often assume laptops, USB drives, tapes and printed reports are covered without writing them down. Close the gap by publishing a short media type register that names each type in use, its owner, and whether it is stored inside or outside a controlled area. Ask the assessor to confirm the register matches what the policy under MP-1 says.
Inventories not reconciled with asset records
A storage inventory that lists cabinets and tapes but does not match the configuration management database or asset register shows that some media are unaccounted for. Auditors often pick a sample of asset records and trace each item to a physical or logical storage location. Close the gap by reconciling the two sources on a set schedule, recording who signed off each difference, and keeping the reconciliation as evidence. Confirm the cadence with your own media protection policy, since NIST does not set one.
Controlled areas not documented
Assessors expect the designated controlled areas where media are stored to be named, bounded and described, with access limited to authorized personnel. When rooms, lockers and vault spaces are known to facilities staff but absent from security documentation, the storage control cannot be tested. Close the gap by drawing each controlled area on a floor plan, listing its access method and authorized roles, and tying it to the physical access records kept under the PE family. Ask facilities to confirm the list before the assessment starts.
Backups stored outside defined areas
Backup copies are media too, and a backup set held in an off-site location, a cloud bucket or a personal drive can fall outside the controlled area the organization defined. Backup tools keep their own catalogs and repositories, so the question is where the data physically or logically sits. Close the gap by listing every backup target against the defined areas, reviewing any target outside them, and checking backup integrity with a tool such as restic, whose check command can read pack files back to confirm the stored data is unmodified.
No evidence of sanitization hand-off
Media that leave storage for destruction or reuse must be protected until they are sanitized, and the hand-off is where protection most often lapses. Without a signed record showing who took custody, when, and what confirmed the sanitization, the assessor cannot verify that protection continued. Close the gap by requiring a custody form for each transfer to sanitization, logging the sanitization method and its verification, and filing the completed record with the inventory. The sanitization control itself is covered under MP-6.
MP-4 media storage questions buyers ask
Does MP-4 media storage apply to low impact systems?
No. SP 800-53B allocates MP-4 to the moderate and high security control baselines only, so a system categorized as low impact does not need to meet it under that baseline. It is also not part of the privacy baseline. Confirm the impact categorization of each system with your authorizing official or risk owner, because the baseline you select follows from that categorization, and any tailoring decision should be documented in the system security and privacy plan. Some agreements or contracts may require MP-4 even for systems that fall below moderate, so check the contract language as well.
How much effort does MP-4 take, and what drives it?
The effort depends mostly on how many media types and storage locations are in scope and how mature your existing records are. Work usually falls into four parts: defining which media types are covered, designating controlled areas, building and maintaining a media inventory, and collecting evidence that storage protections operate. Effort rises when media is spread across many sites, when inventories are maintained by hand, or when no one owns the controlled areas. It falls when media is limited to a few well-defined storage rooms and cabinets with existing access logs. Ask any partner to break its estimate into these parts in writing, and to state which items are one-time setup and which recur each assessment cycle.
Can our team implement MP-4 in-house?
Often yes, if you have staff who understand the system boundary, the physical environment and the assessment procedures. MP-4 is largely a policy, procedure and records control, so the core work is defining media types, designating controlled areas, keeping inventories current and protecting storage until sanitization. Teams without a media owner, or with media stored outside the systems they already manage, usually struggle with the inventory and the controlled-area definitions. Work with facilities and asset management, not only IT security. An outside partner can help if the internal team lacks time or experience, but the organization remains responsible for the control.
What does outside help cover for MP-4, and what stays with us?
An implementation partner can prepare the systems and evidence for MP-4 inside your environment. Typical scope items include:
- Mapping which media types and storage locations fall within the boundary
- Setting up inventory and access logging tools in your own infrastructure
- Configuring encrypted, self-hosted backup and key management where the storage design calls for it
- Documenting procedures and collecting evidence for assessors
The organization still owns the control, decides who is authorized to access storage, and accepts residual risk. Only an independent assessor or certification body issues an assessment result. Agree the boundary of the work, the deliverables and the timeline in writing before work begins.
How long does preparing for MP-4 take?
The duration depends on the size of the environment, how many media types are in scope, and how much remediation the current storage practices need. No preparation timeline has been established for this control, so ask any implementation partner to provide a duration tied to the written scope, and confirm it against your own environment and assessment schedule. Ask for the phases, the dependencies on facilities or procurement, and the points where your staff must review or approve work. Plan for the assessor's schedule separately, since independent assessment is not part of implementation work.
Does NIST certify that we comply with MP-4?
No. NIST publishes SP 800-53 and its assessment procedures, but it does not certify systems, organizations or products, and it does not endorse compliance programs or tools. Your organization determines whether its controls are implemented, and an independent assessor reviews the evidence and reports on it under the applicable program, such as an agency authorization process or a contract. Keep records that let an assessor test MP-4 against the procedures in SP 800-53A, including the media inventory, storage area designations, access records and storage procedures.
How DeployOpen prepares MP-4 storage evidence
DeployOpen plans, implements and documents self-hosted open-source platforms inside the client's own infrastructure, so storage controls for MP-4 sit where the media actually lives. The organization owns its MP-4 control and makes the decisions; DeployOpen prepares the systems, procedures and evidence that an independent assessor will examine.
How we scope
- Agree in writing which media types, storage areas and systems fall under MP-4 before any work starts.
- Confirm the MP-4 baseline applicability with the client, since SP 800-53B allocates MP-4 to moderate and high systems.
- Record the controlled areas, custodians and sanitization dependencies that the written scope must name.
How we build
- Set up inventories of defined media types and their storage locations, with owners recorded for each entry.
- Configure encrypted, access-restricted storage and backup repositories, such as Bareos, restic and Nextcloud server-side encryption, where the client's design calls for them.
- Document the storage procedures and test that the mechanisms behave as the written procedure says they do.
How we hand over
- Deliver the MP-4 procedure, inventory records and configuration exports organized to match the SP 800-53A examine and interview objects.
- Provide test records showing storage mechanisms were exercised, so the client can present them to its assessor.
- Hand over runbooks so the client's own staff can maintain inventories and storage controls after the engagement closes.
How we support
- Support ongoing operation, upgrades and periodic re-testing of storage controls through a retainer, if the client wants it.
- Update the inventory and procedure when media types, storage areas or systems change under the client's change process.
- Note that only an independent assessor or certification body issues assessment conclusions; DeployOpen does not issue attestations.
