The Access Controls (AC) in NIST SP 800-53 specifies the security controls and associated assessment procedures that organizations must implement to protect their information systems and the data they process, store, and transmit. The specific requirements for the AC controls in NIST SP 800-53 include:

1. Identification and Authentication (IA) controls to verify the identity of users, devices, and systems accessing the information system.
2. Authorization controls to determine if a user, device, or system is authorized to access a specific resource.
3. Access control policy and procedures that define the rules and procedures for granting access to information systems and the data they contain.
4. Account Management controls to create, modify, and delete user and device accounts and manage associated privileges.
5. Session Lock and Time-Out controls to limit the duration of an active session and lock the user’s session after a period of inactivity.
6. Remote Access controls to secure remote connections to the information system and the data it contains.
7. Wireless Access controls to secure wireless connections to the information system and the data it contains.
8. Physical Access controls to restrict physical access to information systems and the data they contain.
9. Network Access controls to secure access to the information system over the network.
10. Monitoring controls to track and record events and activities related to access to the information system and the data it contains.

These requirements provide a comprehensive framework for securing information systems and the data they process, store, and transmit.

To meet the Access Controls (AC) requirements specified in NIST SP 800-53, organizations should consider the following recommendations:

1. Implement multi-factor authentication (MFA) to ensure that users are who they claim to be.
2. Define clear roles and responsibilities for system and data access and ensure that authorization is granted based on the principle of least privilege.
3. Develop, document, and implement access control policies and procedures that are consistent with applicable laws, regulations, and standards.
4. Use automated tools to manage user accounts and privileges and ensure that account management processes are secure and auditable.
5. Implement session lock and time-out features to limit the duration of an active session and lock the user’s session after a period of inactivity.
6. Use encryption and secure authentication protocols to secure remote access to the information system and the data it contains.
7. Use wireless access control techniques such as WPA2 encryption, 802.1X authentication, and network segmentation to secure wireless connections.
8. Use physical access controls such as locks, badges, and surveillance cameras to restrict physical access to information systems and the data they contain.
9. Use network access controls such as firewalls, intrusion detection systems, and virtual private networks (VPNs) to secure access to the information system over the network.
10. Implement monitoring controls to track and record events and activities related to access to the information system and the data it contains and perform regular security audits to detect and remediate potential vulnerabilities.

By following these recommendations, organizations can effectively implement and maintain the Access Controls specified in NIST SP 800-53 and protect their information systems and the data they process, store, and transmit.