Vulnerability Discussion

If temporary user accounts remain active when no longer needed or for an excessive period, these accounts may be used to gain unauthorized access. To mitigate this risk, automated termination of all temporary accounts must be set upon account creation.

Temporary accounts are established as part of normal account activation procedures when there is a need for short-term accounts without the demand for immediacy in account activation.

If temporary accounts are used, the operating system must be configured to automatically terminate these types of accounts after a DoD-defined time period of 72 hours.

To address access requirements, many operating systems may be integrated with enterprise-level authentication/access mechanisms that meet or exceed access control policy requirements.

Check

Verify that the Ubuntu operating system expires temporary user accounts within 72 hours or less.

For every existing temporary account, run the following command to obtain its account expiration information:

$ sudo chage -l system_account_name | grep expires

Password expires : Aug 07, 2019
Account expires : Aug 07, 2019

Verify that each of these accounts has an expiration date set within 72 hours of account creation.

If any temporary account does not expire within 72 hours of that account's creation, this is a finding.

Fix

If a temporary account must be created, configure the system to terminate the account after a 72-hour time period with the following command to set an expiration date on it.

Substitute "system_account_name" with the account to be created.

$ sudo chage -E $(date -d "+3 days" +%F) system_account_name