RMF Acronym Cheat Sheet: Every Term ISSOs Actually Use

RMF runs on acronyms. Spend a week in this world and you’ll hear a sentence that’s nearly fifty percent abbreviations, and most guides assume you already know what they mean. This is the reference I wish existed when I started: every acronym that actually comes up in day-to-day RMF and ISSO work, grouped by what they’re for, with a plain explanation of what each one means in practice, not just what the letters stand for.

Bookmark this one. It’s the kind of thing you’ll come back to.

Authorization and Lifecycle

RMF, Risk Management Framework: the six-step process for categorizing, securing, assessing, and authorizing federal information systems.
ATO, Authorization to Operate: the formal decision that a system’s risk is acceptable and it can operate.
IATT, Interim Authorization to Test: a temporary authorization to operate a system in a test environment, not for production use.
ATC, Authorization to Connect: approval for a system to establish a network connection to another system or enclave.
DATO, Denial of Authorization to Operate: the system cannot operate until the issues that led to the denial are resolved.
AO, Authorizing Official: the senior official who reviews the risk and makes the ATO decision.
AODR, Authorizing Official Designated Representative: someone delegated by the AO to handle much of the review work on their behalf.

Core Documentation and Artifacts

SSP, System Security Plan: the foundational document describing the system, its boundary, and how every control is implemented.
POA&M, Plan of Action and Milestones: the tracking document for known weaknesses, their remediation plans, owners, and due dates.
SAP, Security Assessment Plan: describes what will be tested during an assessment and how.
SAR, Security Assessment Report: the results of the assessment, including findings against each control.
SCTM, Security Control Traceability Matrix: a spreadsheet-style mapping of every control to its implementation status, owner, and evidence.
ROC, Risk Outcome (or Overview) Considerations, depending on agency usage: a summary of residual risk presented to support an authorization decision.
RAR, Risk Assessment Report: documents identified threats, vulnerabilities, and the resulting risk level for the system.

Roles You’ll Work With

ISSO, Information System Security Officer: owns the day-to-day security posture of one or more specific systems.
ISSM, Information System Security Manager: oversees a program or portfolio of systems and a team of ISSOs.
ISSE, Information System Security Engineer: designs security into systems at the architecture and engineering level.
SCA, Security Control Assessor: the person or team that independently evaluates whether controls are implemented as documented.
PM, Program Manager: owns the overall program the system belongs to, including budget and schedule.

Systems, Tools, and Scans

eMASS, Enterprise Mission Assurance Support Service: the system of record where DoD RMF packages get built, tracked, and routed for approval.
STIG, Security Technical Implementation Guide: DISA-published configuration standards for hardening specific technologies.
SRG, Security Requirements Guide: a broader configuration standard that STIGs are often derived from for specific products.
SCAP, Security Content Automation Protocol: a standard for automating vulnerability and configuration scans against defined benchmarks.
ACAS, Assured Compliance Assessment Solution: the DoD’s standard vulnerability scanning toolset, built on Tenable Nessus.
CCI, Control Correlation Identifier: a granular breakdown of a control into specific, testable statements, used to link STIG checks back to NIST controls.
CAT I / II / III, Category I, II, III findings: severity levels for STIG findings, with CAT I being the most severe.

Standards and Frameworks

NIST, National Institute of Standards and Technology: publishes the SP 800-series guidance that RMF is built on, including 800-53 (controls) and 800-37 (the RMF process itself).
FIPS, Federal Information Processing Standards: mandatory standards, including FIPS 199, which defines the impact levels used during system categorization.
CUI, Controlled Unclassified Information: sensitive but unclassified data that requires specific safeguarding under federal policy.
CMMC, Cybersecurity Maturity Model Certification: a certification for contractors handling CUI, built on NIST SP 800-171.
FedRAMP, Federal Risk and Authorization Management Program: the program that authorizes cloud service offerings for federal use.
IL, Impact Level: DoD’s classification (IL2 through IL6) of how sensitive the data in a given cloud environment can be.
C3PAO, Certified Third-Party Assessment Organization: accredited external bodies that perform CMMC Level 2 assessments.

Ongoing Operations

ConMon, Continuous Monitoring: the ongoing process of tracking a system’s security posture after authorization, including scans, patching, and POA&M updates.
CM, Configuration Management: the discipline of tracking and controlling changes to a system’s hardware, software, and settings.
CCB, Configuration Control Board: the group that reviews and approves proposed changes to a system, often with a security representative present.
SIA, Security Impact Analysis: an assessment of how a proposed change affects the system’s security posture and existing authorization.

Final Thoughts

None of these acronyms are complicated on their own. What makes RMF feel impenetrable early on is hearing five of them strung together in one sentence before you’ve built a mental map of how they relate to each other. Once you can place each term in the lifecycle, who owns it, and what it feeds into, the acronym soup turns into a fairly logical system.

If a term comes up that isn’t here, that’s useful to know, RMF terminology varies somewhat by agency and program, and this list will keep growing as the gaps show up.

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