Internet with Safe Zones for Picture Download must be disabled.

From Microsoft Outlook 2013 STIG

Part of DTOO274 - Internet with Safe Zones

SV-54048r1_rule Internet with Safe Zones for Picture Download must be disabled.

Vulnerability discussion

Malicious email senders can send HTML email messages with embedded Web beacons, which are pictures and other content from external servers that can be used to track whether recipients open the messages. Viewing email messages that contain Web beacons provides confirmation that the recipient's email address is valid, which leaves the recipient vulnerable to additional spam and harmful email.By default, Outlook does not download external content in HTML email messages from untrusted senders via the Internet. If this configuration is changed, Outlook will display external content in all HTML email messages received from the Internet, which could include Web beacons.

Check content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Security -> Automatic Picture Download Settings "Include Internet in Safe Zones for Automatic Picture Download" is set to "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\outlook\options\mail Criteria: If the value Internet is REG_DWORD = 0, this is not a finding.

Fix text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2013 -> Security -> Automatic Picture Download Settings "Include Internet in Safe Zones for Automatic Picture Download" to "Disabled".

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.