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4.2.21 Ensure SSH MaxSessions is set to 10 or less

Information

The MaxSessions parameter specifies the maximum number of open sessions permitted from a given connection.

To protect a system from denial of service due to a large number of concurrent sessions, use the rate limiting function of MaxSessions to protect availability of sshd logins and prevent overwhelming the daemon.

Solution

Edit the /etc/ssh/sshd_config file to set the parameter as follows:

MaxSessions 10

Note: First occurrence of a option takes precedence, Match set statements withstanding.

See Also

https://workbench.cisecurity.org/benchmarks/13007

Item Details

Category: CONFIGURATION MANAGEMENT, IDENTIFICATION AND AUTHENTICATION

References: 800-53|CM-1, 800-53|CM-2, 800-53|CM-6, 800-53|CM-7, 800-53|IA-5

Plugin: Unix

Control ID: 69b9c96fa43f84513234eebc3453f2e5086d8a6b51d5403521b097e0ca957c32