The cybersecurity maturity model certification has 17 capability domains. The first domain and the one applying to all CMMC levels is the Access Control domain. The access control domain has four capability requirements and a total of twenty-six practices.

Access control is a method of guaranteeing that users are who they say they are and that they have the appropriate access to company data. (Source)

The goal of the access control domain is to limit access to your systems and data. This includes limiting who can log into your systems. Limiting system access to authorized devices. Limiting permissions so that users, devices, and processes can only access the resources they need to fulfill business requirements.

• C001: Establish system access requirements
• C002: Control internal system access
• C003: Control remote system access
• C004: Limit data access to authorized users and processes

Examples of access control security requirements include account management, separation of duties, least privilege, session lock, information flow enforcement, and session termination controls.