AOSX-14-000050 - The macOS system must limit the number of concurrent SSH sessions to 10 for all accounts and/or account types.
Operating system management includes the ability to control the number of users and user sessions that utilize an operating system. Limiting the number of allowed users and sessions per user is helpful in reducing the risks related to DoS attacks. This requirement addresses concurrent sessions for information system accounts and does not address concurrent sessions by single users via multiple system accounts. The maximum number of concurrent sessions should be defined based upon mission needs and the operational environment for each system.
To configure SSHD to limit the number of sessions, use the following command: /usr/bin/sudo /usr/bin/sed -i.bak 's/^[#]*MaxSessions.*/MaxSessions 10/' /etc/ssh/sshd_config