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

From Canonical Ubuntu 16.04 Security Technical Implementation Guide

Associated with: CCI-000054

SV-90123r2_rule The Ubuntu operating system must limit the number of concurrent sessions to ten for all accounts and/or account types.

Vulnerability discussion

Ubuntu operating system management includes the ability to control the number of users and user sessions that utilize an Ubuntu 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.

Check content

Verify that the Ubuntu operating system limits the number of concurrent sessions to "10" for all accounts and/or account types by running the following command: # grep maxlogins /etc/security/limits.conf The result must contain the following line: * hard maxlogins 10 If the "maxlogins" item is missing or the value is not set to "10" or less, or is commented out, this is a finding.

Fix text

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

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