Add-on Management must be enabled for all Office 365 ProPlus programs.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-99667	O365-CO-000014	SV-108771r1_rule		Medium

Description
Internet Explorer add-ons are pieces of code, run in Internet Explorer, to provide additional functionality. Rogue add-ons may contain viruses or other malicious code. Disabling or not configuring this setting could allow malicious code or users to become active on user computers or the network. For example, a malicious user can monitor and then use keystrokes that user's type into Internet Explorer. Even legitimate add-ons may demand resources, compromising the performance of Internet Explorer and the operating systems for user computers.

Description

Internet Explorer add-ons are pieces of code, run in Internet Explorer, to provide additional functionality. Rogue add-ons may contain viruses or other malicious code. Disabling or not configuring this setting could allow malicious code or users to become active on user computers or the network. For example, a malicious user can monitor and then use keystrokes that user's type into Internet Explorer. Even legitimate add-ons may demand resources, compromising the performance of Internet Explorer and the operating systems for user computers.

STIG	Date
Microsoft Office 365 ProPlus Security Technical Implementation Guide	2020-06-17

Details

Check Text ( C-98517r1_chk )
Verify the policy value for Computer Configuration >> Administrative Templates >> Microsoft Office 2016 (Machine) >> Security Settings >> IE Security "Add-on Management" is set to "Enabled" and the check box is selected for every installed Office program. Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_ADDON_MANAGEMENT If the value for each installed Office Program is REG_DWORD = 1, this is not a finding.

Check Text ( C-98517r1_chk )

Verify the policy value for Computer Configuration >> Administrative Templates >> Microsoft Office 2016 (Machine) >> Security Settings >> IE Security "Add-on Management" is set to "Enabled" and the check box is selected for every installed Office program.

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

HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_ADDON_MANAGEMENT

If the value for each installed Office Program is REG_DWORD = 1, this is not a finding.

Fix Text (F-105351r1_fix)
Set the policy value for Computer Configuration >> Administrative Templates >> Microsoft Office 2016 (Machine) >> Security Settings >> IE Security "Add-on Management" to "Enabled" and select the check boxes for all installed Office programs.