The Ubuntu operating system must not have unnecessary accounts.

From Canonical Ubuntu 16.04 Security Technical Implementation Guide

Associated with: CCI-000366

SV-90225r2_rule The Ubuntu operating system must not have unnecessary accounts.

Vulnerability discussion

Accounts providing no operational purpose provide additional opportunities for system compromise. Unnecessary accounts include user accounts for individuals not requiring access to the system and application accounts for applications not installed on the system.

Check content

Verify all accounts on the system are assigned to an active system, application, or user account. Obtain the list of authorized system accounts from the Information System Security Officer (ISSO). Check the system accounts on the system with the following command: # more /etc/passwd root:x:0:0:root:/root:/bin/bash ... games:x:5:60:games:/usr/games:/usr/sbin/nologin Accounts such as "games" and "gopher" are not authorized accounts as they do not support authorized system functions. If the accounts on the system do not match the provided documentation, or accounts that do not support an authorized system function are present, this is a finding.

Fix text

Configure the system so all accounts on the system are assigned to an active system, application, or user account. Remove accounts that do not support approved system activities or that allow for a normal user to perform administrative-level actions. Document all authorized accounts on the system.

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