Details

The operating system must limit the number of concurrent sessions to 10 for all accounts and/or account types.

Rationale:

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 on mission needs and the operational environment for each system.

Solution

Configure the operating system to limit the number of concurrent sessions to 10 for all accounts and/or account types.
Example: vim /etc/security/limits.conf
Add the following line to the top of the /etc/security/limits.conf:

* hard maxlogins 10

Supportive Information

The following resource is also helpful.

• https://workbench.cisecurity.org/files/3636

This security hardening control applies to the following category of controls within NIST 800-53: Access Control.This control applies to the following type of system Unix.

References

• 800-53|AC-10
• CCI|CCI-000054
• Rule-ID|SV-204576r603261_rule
• STIG-ID|RHEL-07-040000

Source

• Tenable.com/audits