Requirement
Require multifactor authentication to establish nonlocal maintenance sessions via external network connections and terminate such connections when nonlocal maintenance is complete.
Assessment Objectives
- Multifactor authentication is used to establish nonlocal maintenance sessions via external network connections
- Nonlocal maintenance sessions established via external network connections are terminated when nonlocal maintenance is complete
Potential Assessment Methods and Objects [NIST SP 800-171A]
Examine
- System maintenance policy
- Procedures addressing nonlocal system maintenance
- System security plan
- System design documentation
- System configuration settings and associated documentation
- Maintenance records
- Diagnostic records
- Other relevant documents or records
Interview
- Personnel with system maintenance responsibilities
- Personnel with information security responsibilities
- System or network administrators
Test
- Organizational processes for managing nonlocal maintenance
- Mechanisms implementing, supporting, or managing nonlocal maintenance
- Mechanisms for strong authentication of nonlocal maintenance diagnostic sessions
Discussion [NIST SP 800-171 REV. 2]
Nonlocal maintenance and diagnostic activities are those activities conducted by individuals communicating through an external network. The authentication techniques employed in the establishment of these nonlocal maintenance and diagnostic sessions reflect the network access requirements in IA.L2-3.5.3.
Further Discussion
Nonlocal maintenance activities must use multifactor authentication. Multifactor authentication requires at least two factors, such as: something you know (e.g., password, personal identification number [PIN]); something you have (e.g., cryptographic identification device, token); or something you are (e.g., biometric fingerprint or facial scan). Requiring two or more factors to prove your identity increases the security of the connection. Nonlocal maintenance activities are activities conducted from external network connections such as over the internet. After nonlocal maintenance activities are complete, shut down the external network connection.
Examples
Example 1
You are responsible for maintaining your company's firewall. In order to conduct maintenance while working remotely, you connect to the firewall's management interface and log in using administrator credentials. The firewall then sends a verification request to the multifactor authentication app on your smartphone [a]. You need both of these things to prove your identity [a]. After you respond to the multifactor challenge, you have access to the maintenance interface. When you finish your activities, you shut down the remote connection by logging out and quitting your web browser [b].
Potential Assessment Considerations
- Is multifactor authentication required for establishing nonlocal maintenance sessions via external network connections [a]?
- Are nonlocal maintenance sessions terminated when complete [b]?
References
- NIST SP 800-171 Rev. 2 3.7.5
