Title

Internet with Safe Zones for Picture Download must be disabled. (Cat II impact)

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".

Additional Identifiers

Rule ID: SV-54048r1_rule

Vulnerability ID: V-17630

Group Title: DTOO274 - Internet with Safe Zones

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.