Catalina - Automatically Remove or Disable Temporary or Emergency User Accounts within 72 Hours

Information

The macOS is able to be configured to set an automated termination for 72 hours or less for all temporary or emergency accounts upon account creation.

Emergency administrator accounts are privileged accounts established in response to crisis situations where the need for rapid account activation is required. Therefore, emergency account activation may bypass normal account authorization processes. If these accounts are disabled, system maintenance during emergencies may not be possible, thus adversely affecting system availability.

Although the ability to create and use emergency administrator accounts is necessary for performing system maintenance during emergencies, these accounts present vulnerabilities to the system if they are not disabled and removed when they are no longer needed. Configuring the macOS to automatically remove or disable emergency accounts within 72 hours of creation mitigates the risks posed if one were to be created and accidentally left active once the crisis is resolved.

Emergency administrator accounts are different from infrequently used accounts (i.e., local logon accounts used by system administrators when network or normal logon is not available). Infrequently used accounts also remain available and are not subject to automatic termination dates. However, an emergency administrator account is normally a different account created for use by vendors or system maintainers.

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

If temporary or emergency user accounts remain active when no longer needed or for an excessive period, these accounts may be targeted by attackers to gain unauthorized access. To mitigate this risk, automated termination of all temporary or emergency accounts _MUST_ be set to 72 hours (or less) when the temporary or emergency account is created.

If no policy is enforced by a directory service, a password policy can be set with the "pwpolicy" utility. The variable names may vary depending on how the policy was set.

If there are no temporary or emergency accounts defined on the system, this is Not Applicable.

NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.

Solution

This setting may be enforced using local policy or by a directory service.

To set local policy to disable a temporary or emergency user, create a plain text file containing the following:

<dict>
<key>policyCategoryAuthentication</key>
<array>
<dict>
<key>policyContent</key>
<string>policyAttributeCurrentTime < policyAttributeCreationTime+259299</string>
<key>policyIdentifier</key>
<string>Disable Tmp Accounts </string>
</dict>
</array>
</dict>

After saving the file and exiting to the command prompt, run the following command to load the new policy file, substituting the correct user name in place of "username" and the path to the file in place of "/path/to/file".

/usr/bin/pwpolicy -u username setaccountpolicies /path/to/file

Item Details

Audit Name: NIST macOS Catalina v1.5.0 - 800-53r5 Moderate

Category: ACCESS CONTROL

Plugin: Unix

Control ID: e1716d8f1a5fa7b4083ca9b3225e4c9ff7911a840dbd1485961533a32f0159c4

Detections

Analytics

Catalina - Automatically Remove or Disable Temporary or Emergency User Accounts within 72 Hours

Information

Solution

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Item Details