The Ubuntu operating system must not have accounts configured with blank or null passwords.

From Canonical Ubuntu 16.04 Security Technical Implementation Guide

Associated with: CCI-000366

SV-90159r1_rule The Ubuntu operating system must not have accounts configured with blank or null passwords.

Vulnerability discussion

If an account has an empty password, anyone could log on and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.

Check content

To verify that null passwords cannot be used, run the following command: # grep pam_unix.so /etc/pam.d/* | grep nullok If this produces any output, it may be possible to log on with accounts with empty passwords. If null passwords can be used, this is a finding.

Fix text

If an account is configured for password authentication but does not have an assigned password, it may be possible to log on to the account without authenticating. Remove any instances of the "nullok" option in files under "/etc/pam.d/" to prevent logons with empty passwords.

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