CM-7(1)—Least Functionality | Periodic Review

IL4 Mod

IL4 High

IL5

IL6

>Control Description

(a) Review the system ⚙organization-defined frequency to identify unnecessary and/or nonsecure functions, ports, protocols, software, and services; and (b) Disable or remove ⚙organization-defined functions, ports, protocols, software, and services within the system deemed to be unnecessary and/or nonsecure.

>DoD Impact Level Requirements

FedRAMP Parameter Values

CM-7 (1) (a) [at least annually]

>Discussion

Organizations review functions, ports, protocols, and services provided by systems or system components to determine the functions and services that are candidates for elimination. Such reviews are especially important during transition periods from older technologies to newer technologies (e.g., transition from IPv4 to IPv6). These technology transitions may require implementing the older and newer technologies simultaneously during the transition period and returning to minimum essential functions, ports, protocols, and services at the earliest opportunity.

Organizations can either decide the relative security of the function, port, protocol, and/or service or base the security decision on the assessment of other entities. Unsecure protocols include Bluetooth, FTP, and peer-to-peer networking.

>Programmatic Queries

Beta

Related Services

AWS Security Hub

Amazon Inspector

CLI Commands

List unused security groups for review

aws ec2 describe-security-groups --region us-east-1 --query 'SecurityGroups[?IpPermissions==`[]` && IpPermissionsEgress==`[]`]'

Get Inspector findings for unnecessary functionality

aws inspector2 list-findings --filter-criteria '{"resourceType": [{"comparison": "EQUALS", "value": "EC2"}]}' --region us-east-1

Describe unused IAM roles and policies

aws iam get-credential-report --download-path /tmp/credential-report.csv

Review unused VPC endpoints

aws ec2 describe-vpc-endpoints --region us-east-1 --query 'VpcEndpoints[?State==`available`]'

Open AWS Console Documentation

>Related Controls

AC-18

>Assessment Interview Topics

Questions assessors commonly ask

Process & Governance:

•What formal policies and procedures govern the implementation of CM-7(1) (Periodic Review)?
•Who are the designated roles responsible for implementing, maintaining, and monitoring CM-7(1)?
•How frequently is the CM-7(1) policy reviewed and updated, and what triggers policy changes?
•What training or awareness programs ensure personnel understand their responsibilities related to CM-7(1)?

Technical Implementation:

•Describe the specific technical mechanisms or controls used to enforce CM-7(1) requirements.
•What automated tools, systems, or technologies are deployed to implement CM-7(1)?
•How is CM-7(1) integrated into your system architecture and overall security posture?
•What configuration settings, parameters, or technical specifications enforce CM-7(1) requirements?

Evidence & Documentation:

•What documentation demonstrates the complete implementation of CM-7(1)?
•What audit logs, records, reports, or monitoring data validate CM-7(1) compliance?
•Can you provide evidence of periodic reviews, assessments, or testing of CM-7(1) effectiveness?
•What artifacts would you present during a FedRAMP assessment to demonstrate CM-7(1) compliance?

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