The IIS 10.0 web server must not be both a website server and a proxy server.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-218794	IIST-SV-000119	SV-218794r561041_rule		Medium

Description
A web server should be primarily a web server or a proxy server but not both, for the same reasons that other multi-use servers are not recommended. Scanning for web servers that also proxy requests into an otherwise protected network is a common attack, making the attack anonymous.

STIG	Date
Microsoft IIS 10.0 Server Security Technical Implementation Guide	2021-12-10

Details

Check Text ( C-20266r310857_chk )
Open the IIS 10.0 Manager. Under the "Connections" pane on the left side of the management console, select the IIS 10.0 web server. If, under the IIS installed features, "Application Request Routing Cache" is not present, this is not a finding. If, under the IIS installed features, "Application Request Routing Cache" is present, double-click the icon to open the feature. From the right "Actions" pane, under "Proxy", select "Server Proxy Settings...". In the "Application Request Routing" settings window, verify whether "Enable proxy" is selected. If “Enable proxy" is selected under the "Application Request Routing" settings, this is a finding.

Check Text ( C-20266r310857_chk )

Open the IIS 10.0 Manager.

Under the "Connections" pane on the left side of the management console, select the IIS 10.0 web server.

If, under the IIS installed features, "Application Request Routing Cache" is not present, this is not a finding.

If, under the IIS installed features, "Application Request Routing Cache" is present, double-click the icon to open the feature.

From the right "Actions" pane, under "Proxy", select "Server Proxy Settings...".

In the "Application Request Routing" settings window, verify whether "Enable proxy" is selected.

If “Enable proxy" is selected under the "Application Request Routing" settings, this is a finding.

Fix Text (F-20264r310858_fix)
Open the IIS 10.0 Manager. Under the "Connections" pane on the left side of the management console, select the IIS 10.0 web server. Under the IIS installed features, "Application Request Routing Cache" is present, double-click the icon to open the feature. From the right "Actions" pane, under "Proxy", select "Server Proxy Settings...". In the "Application Request Routing" settings window, remove the check from the "Enable proxy" check box. Click "Apply" in the "Actions" pane.

Fix Text (F-20264r310858_fix)

Open the IIS 10.0 Manager.

Under the "Connections" pane on the left side of the management console, select the IIS 10.0 web server.

Under the IIS installed features, "Application Request Routing Cache" is present, double-click the icon to open the feature.

From the right "Actions" pane, under "Proxy", select "Server Proxy Settings...".

In the "Application Request Routing" settings window, remove the check from the "Enable proxy" check box.

Click "Apply" in the "Actions" pane.