Requirement
FAR 52.204-21 / CMMC 2.0 Level 1 - Control - AC.L1-B.1.IV – Control information posted or processed on publicly accessible information systems.
Understanding the Requirement
This control requires that organizations prevent Controlled Unclassified Information (CUI) from being posted or processed on publicly accessible systems by limiting who can post, establishing review procedures, and ensuring a review process is applied before any public posting. As part of FAR 52.204-21 / CMMC 2.0 Level 1, the objectives include identifying authorized posters, documenting procedures that prevent CUI disclosure, performing pre-publication reviews, continuously reviewing public content, and having mechanisms to remove and remediate improper postings.
Technical Implementation
-
Define and enforce posting roles and permissions.
Create a small roster of authorized publishers (e.g., a marketing lead, social media manager, and an appointed security reviewer). Enforce these roles in your CMS and social platforms by using unique accounts, strong authentication (MFA), and role-based access controls so only designated accounts can publish to public channels.
-
Implement a staged publishing workflow with mandatory review.
Require all public content to pass through a staging environment or an approval workflow that includes a checklist for CUI. The checklist should require confirmation that no CUI, contract details, sensitive technical specs, or unredacted contract identifiers are included. Use the CMS approval pipeline so content cannot be published until approval is recorded.
-
Use automated scanning for likely CUI indicators.
Deploy lightweight Data Loss Prevention (DLP) or regular-expression based scanning tools that check drafts for keywords, contract numbers, technical data patterns, or other CUI markers. Integrate scans into the staging workflow to flag risky posts and require manual review if the scanner detects potential CUI.
-
Train staff and document procedures.
Provide concise training for authorized posters and reviewers that explains what CUI looks like in your business context (examples: contract numbers, program names, technical specs). Publish a simple posting policy and a one-page checklist that reviewers must complete before approving posts.
-
Establish rapid takedown and remediation processes.
Maintain a documented incident procedure for removal of improperly posted CUI: who to notify, how to remove content, how to document the event, and how to notify affected parties if required. Keep administrative access for quick takedown and preserve logs and backups for forensic review and learning.
-
Monitor and audit public content regularly.
Schedule periodic scans of your public website and social feeds (weekly or monthly depending on volume) to catch any missed exposures. Record results, remediate finds, and update controls or training based on root cause.
Example in a Small or Medium Business
Acme Tech, a 50-person IT services firm, recently won a federal subcontract and their marketing team prepared a celebratory press release. Under the firm’s posting policy, only the marketing lead and a designated security reviewer can publish to the company website and official social accounts. The marketing lead uploads the draft to the CMS staging area where an automated scanner checks for contract numbers, program names, and technical phrases associated with CUI. The scanner flags a line that includes a contract identifier; the marketing lead routes the draft to the security reviewer who consults the contract and confirms the identifier must be redacted. After redaction, the reviewer completes the pre-publication checklist (confirming no CUI, approval recorded), and the content is approved for publishing. The post goes live and the social post is limited to a short, pre-approved excerpt that contains no program-specific details. A week later an internal audit scan of public pages finds no CUI; the team documents the workflow success and updates training so junior staff understand the redaction rule.
Summary
Combining clear policies (who may post and what must be reviewed), a technical publishing workflow (staging, RBAC, MFA, automated scanning), and an incident/takedown process ensures CUI is not published on public systems. For SMBs this approach minimizes accidental disclosure by restricting posting privileges, enforcing pre-publication checks, scanning drafts for CUI indicators, training staff, and providing a fast remediation path when mistakes occur — together meeting the control’s objectives in a practical, repeatable way.
