2.5.14.4.1 Ensure 'Allow hyperlinks in suspected phishing e-mail messages' is set to 'Disabled'

Information

This policy setting controls whether hyperlinks in suspected phishing e-mail messages in Outlook are allowed.

By default, Outlook handles suspicious messages in two ways:

If the Junk E-mail Filter does not consider a message to be spam but does consider it to be phishing, the message is left in the Inbox but any links in the message are disabled and users cannot use the Reply and Reply All functionality. In addition, any attachments in the suspicious message are blocked.

If the Junk E-mail Filter considers the message to be both spam and phishing, the message is automatically sent to the Junk E-mail folder. Any message sent to the Junk E-mail folder is converted to plain text format and all links are disabled. In addition, the Reply and Reply All functionality is disabled and any attachments in the message are blocked.

The InfoBar alerts users to this change in functionality. If users are certain that a message is legitimate, they can click the InfoBar and enable the links in the message.

Users can change the way Outlook handles phishing messages in the Junk E-mail Options dialog box by clearing the Disable links and other functionality in phishing messages (Recommended) check box. If this check box is cleared, Outlook will not disable links in suspected phishing messages unless they are classified as junk e-mail, which could allow users to disclose confidential information to malicious Web sites.

The recommended state for this setting is: Disabled.

Rationale:

Outlooks Junk E-mail Filter evaluates each incoming message for possible spam or phishing content. Allowing this functionality could stop users from clicking on malicious emails.

Impact:

None - this is the default behavior.

Solution

To establish the recommended configuration via GP, set the following UI path to Disabled:

User Configuration\Administrative Templates\Microsoft Outlook 2016\Security\Trust Center\Allow hyperlinks in suspected phishing e-mail messages

Default Value:

Disabled. (Outlook will not allow hyperlinks in suspected phishing messages, even if they are not classified as junk e-mail.)

See Also

https://workbench.cisecurity.org/benchmarks/12129

Item Details

Category: SYSTEM AND INFORMATION INTEGRITY

References: 800-53|SI-3, 800-53|SI-8, 800-53|SI-16

Plugin: Windows

Control ID: 80c2dc3ec039c8486fdf89cc42a5bdb93345c44b1b2eec88f9330b3f6d16a314