Intranet with Safe Zones for automatic picture downloads must be configured.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-17634	DTOO275 - Outlook	SV-33562r2_rule		Medium

Description
Malicious e-mail senders can send HTML e-mail 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 e-mail messages with Web beacons in them provides confirmation that the recipient's e-mail address is valid, which leaves the recipient vulnerable to additional spam and harmful e-mail. By default, Outlook does not download external content in HTML e-mail messages from untrusted senders over the local intranet. If this configuration is changed, Outlook will display external content in all HTML e-mail messages received via the local intranet, which could include Web beacons.

Description

Malicious e-mail senders can send HTML e-mail 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 e-mail messages with Web beacons in them provides confirmation that the recipient's e-mail address is valid, which leaves the recipient vulnerable to additional spam and harmful e-mail. By default, Outlook does not download external content in HTML e-mail messages from untrusted senders over the local intranet. If this configuration is changed, Outlook will display external content in all HTML e-mail messages received via the local intranet, which could include Web beacons.

STIG	Date
Microsoft Outlook 2010 STIG	2018-04-04

Details

Check Text ( C-34021r1_chk )
The policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2010 -> Security -> Automatic Picture Download Settings “Include Intranet in Safe Zones for Automatic Picture Download” must be set to “Disabled”. Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\14.0\outlook\options\mail Criteria: If the value Intranet is REG_DWORD = 0, this is not a finding.

Check Text ( C-34021r1_chk )

The policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2010 -> Security -> Automatic Picture Download Settings “Include Intranet in Safe Zones for Automatic Picture Download” must be set to “Disabled”.

Procedure: Use the Windows Registry Editor to navigate to the following key:

HKCU\Software\Policies\Microsoft\Office\14.0\outlook\options\mail

Criteria: If the value Intranet is REG_DWORD = 0, this is not a finding.

Fix Text (F-29708r1_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2010 -> Security -> Automatic Picture Download Settings “Include Intranet in Safe Zones for Automatic Picture Download” to “Disabled”.