cis-gworkspace-3-1-3-5-4

name	cis-gworkspace-3.1.3.5.4
description	Ensure external recipient warnings are enabled
category	cis-gworkspace
version	1.3.0
author	cyberstrike-official
tags	["cis","gcp","google-workspace","gmail","forwarding"]
cis_id	3.1.3.5.4
cis_benchmark	CIS Google Workspace Foundations Benchmark v1.3.0
tech_stack	["gcp","google-workspace"]
cwe_ids	[]
chains_with	[]
prerequisites	[]
severity_boost	{}

Ensure external recipient warnings are enabled (Manual)

Description

Gmail adds an image or colored border to external addresses.

Rationale

As an admin for your organization, you can turn alerts on or off for messages that include external recipients (people with email addresses outside of your organization). These alerts help people avoid unintentional replies, and remind them to treat external messages with caution.

Impact

When this setting is on, Gmail shows warnings (colored border) when:

• An email thread includes external recipients (not available on iOS).
• Replying to a message from an external recipient.
• Composing a new message to an external recipient (not available on iOS).

Gmail doesn't show a warning if the external recipient is in your organization's Directory, personal Contacts, or other Contacts. Warnings aren't displayed for secondary domain or domain alias addresses.

Audit Procedure

Using Google Workspace Admin Console

1. Log in to https://admin.google.com as an administrator
2. Select Apps
3. Select Google Workspace
4. Select Gmail
5. Select End User Access
6. Under Warn for external recipients, ensure Highlight any external recipients in a conversation. Warn users before they reply to email with external recipients who aren't in their contacts. is ON

Expected Result

Highlight any external recipients in a conversation. Warn users before they reply to email with external recipients who aren't in their contacts. should be ON.

Remediation

Using Google Workspace Admin Console

1. Log in to https://admin.google.com as an administrator
2. Select Apps
3. Select Google Workspace
4. Select Gmail
5. Select End User Access
6. Select Warn for external recipients
7. Set Highlight any external recipients in a conversation. Warn users before they reply to email with external recipients who aren't in their contacts. to checked
8. Select Save

Default Value

is