External content and pictures in HTML eMail must be displayed.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-17672	DTOO270 - Outlook	SV-33548r1_rule	ECSC-1	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 specific recipients open the message. Viewing an e-mail message that contains a Web beacon 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 and RSS items unless the content is considered safe. Content that Outlook can be configured to consider safe includes: • Content in e-mail messages from senders and to recipients defined in the Safe Senders and Safe Recipients lists. • Content from Web sites in Internet Explorer's Trusted Sites security zone. • Content in RSS items. • Content from SharePoint Discussion Boards. Users can control what content is considered safe by changing the options in the Automatic Download section of the Trust Center. If Outlook's default blocking configuration is overridden, in the Trust Center or by some other method, Outlook will display external content in all HTML e-mail messages, including any that 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 specific recipients open the message. Viewing an e-mail message that contains a Web beacon 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 and RSS items unless the content is considered safe. Content that Outlook can be configured to consider safe includes: • Content in e-mail messages from senders and to recipients defined in the Safe Senders and Safe Recipients lists. • Content from Web sites in Internet Explorer's Trusted Sites security zone. • Content in RSS items. • Content from SharePoint Discussion Boards. Users can control what content is considered safe by changing the options in the Automatic Download section of the Trust Center. If Outlook's default blocking configuration is overridden, in the Trust Center or by some other method, Outlook will display external content in all HTML e-mail messages, including any that include Web beacons.

STIG	Date
Microsoft Outlook 2010	2014-04-03

Details

Check Text ( C-34015r1_chk )
The policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2010 -> Security -> Automatic Picture Download Settings “Display pictures and external content in HTML e-mail” must be set to “Enabled”. 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 BlockExtContent is REG_DWORD = 0, this is not a finding.

Check Text ( C-34015r1_chk )

The policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2010 -> Security -> Automatic Picture Download Settings “Display pictures and external content in HTML e-mail” must be set to “Enabled”.

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 BlockExtContent is REG_DWORD = 0, this is not a finding.

Fix Text (F-29703r1_fix)
Set the policy value for User Configuration -> Administrative Templates -> Microsoft Outlook 2010 -> Security -> Automatic Picture Download Settings “Display pictures and external content in HTML e-mail” to “Enabled”.