Organizational Control: Remote Access

Control ID: AC-17 Remote Access Family: Access Control Source: NIST 800-53r4
Control: The organization:
  1. Establishes and documents usage restrictions, configuration/connection requirements, and implementation guidance for each type of remote access allowed; and
  2. Authorizes remote access to the information system prior to allowing such connections.
Supplemental Guidance:
Remote access is access to organizational information systems by users (or processes acting on behalf of users) communicating through external networks (e.g.,the Internet). Remote access methods include, for example, dial-up, broadband, and wireless. Organizations often employ encrypted virtual private networks (VPNs) to enhance confidentiality and integrity over remote connections. The use of encrypted VPNs does not make the access non-remote; however, the use of VPNs, when adequately provisioned with appropriate security controls (e.g., employing appropriate encryption techniques for confidentiality and integrity protection) may provide sufficient assurance to the organization that it can effectively treat such connections as internal networks. Still, VPN connections traverse external networks, and the encrypted VPN does not enhance the availability of remote connections. Also, VPNs with encrypted tunnels can affect the organizational capability to adequately monitor network communications traffic for malicious code. Remote access controls apply to information systems other than public web servers or systems designed for public access. This control addresses authorization prior to allowing remote access without specifying the formats for such authorization. While organizations may use interconnection security agreements to authorize remote access connections, such agreements are not required by this control. Enforcing access restrictions for remote connections is addressed in AC-3.

Related Controls: AC-2, AC-3, AC-19, AC-20, CA-3, CA-7, CM-8, IA-2, MA-4, PE-17, PL-4, SI-4, AC-18, IA-3, IA-8, SC-10
Control Enhancements:
(1) Remote Access | Automated Monitoring / Control
The information system monitors and controls remote access methods.
Supplemental Guidance: Automated monitoring and control of remote access sessions allows organizations to detect cyber attacks and also ensure ongoing compliance with remote access policies by auditing connection activities of remote users on a variety of information system components (e.g.,servers, workstations, notebook computers, smart phones, and tablets).
Related Controls: AU-2, AU-12

(2) Remote Access | Protection Of Confidentiality / Integrity Using Encryption
The information system implements cryptographic mechanisms to protect the confidentiality and integrity of remote access sessions.
Supplemental Guidance: The encryption strength of mechanism is selected based on the security categorization of the information.
Related Controls: N/A
References: NIST Special Publications 800-46, 800-77, 800-113, 800-114, 800-121.
Mechanisms:

Protocol Implementation Conformance Statements: N/A