The IIS 8.5 website must employ cryptographic mechanisms (TLS) preventing the unauthorized disclosure of information during transmission.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-76853	IISW-SI-000243	SV-91549r1_rule		Medium

Description
Preventing the disclosure of transmitted information requires that the web server take measures to employ some form of cryptographic mechanism in order to protect the information during transmission. This is usually achieved through the use of Transport Layer Security (TLS). Transmission of data can take place between the web server and a large number of devices/applications external to the web server. Examples are a web client used by a user, a backend database, an audit server, or other web servers in a web cluster. If data is transmitted unencrypted, the data then becomes vulnerable to disclosure. The disclosure may reveal user identifier/password combinations, website code revealing business logic, or other user personal information.

Description

Preventing the disclosure of transmitted information requires that the web server take measures to employ some form of cryptographic mechanism in order to protect the information during transmission. This is usually achieved through the use of Transport Layer Security (TLS). Transmission of data can take place between the web server and a large number of devices/applications external to the web server. Examples are a web client used by a user, a backend database, an audit server, or other web servers in a web cluster. If data is transmitted unencrypted, the data then becomes vulnerable to disclosure. The disclosure may reveal user identifier/password combinations, website code revealing business logic, or other user personal information.

STIG	Date
IIS 8.5 Site Security Technical Implementation Guide	2018-01-03

Details

Check Text ( C-76509r1_chk )
Follow the procedures below for each site hosted on the IIS 8.5 web server: Open the IIS 8.5 Manager. Double-click the "SSL Settings" icon under the "IIS" section. Verify "Require SSL" is checked. Verify "Client Certificates Required" is selected. Click the site under review. Under "Configuration Editor" under the "Management" section. From the "Section:" drop-down list at the top of the configuration editor, locate “system.webServer/security/access”. The value for "sslFlags" should be ssl128. If the "Require SSL" is not selected, this is a finding. If the "Client Certificates Required" is not selected, this is a finding. If the "sslFlags" is not set to "ssl128", this is a finding.

Check Text ( C-76509r1_chk )

Follow the procedures below for each site hosted on the IIS 8.5 web server:

Open the IIS 8.5 Manager.

Double-click the "SSL Settings" icon under the "IIS" section.

Verify "Require SSL" is checked.

Verify "Client Certificates Required" is selected.

Click the site under review.

Under "Configuration Editor" under the "Management" section.

From the "Section:" drop-down list at the top of the configuration editor, locate “system.webServer/security/access”.

The value for "sslFlags" should be ssl128.

If the "Require SSL" is not selected, this is a finding.

If the "Client Certificates Required" is not selected, this is a finding.

If the "sslFlags" is not set to "ssl128", this is a finding.

Fix Text (F-83549r1_fix)
Follow the procedures below for each site hosted on the IIS 8.5 web server: Open the IIS 8.5 Manager. Double-click the "SSL Settings" icon under the "IIS" section. Select the "Require SSL" setting. Select the "Client Certificates Required" setting. Click "Apply" in the "Actions" pane. Click the site under review. Under "Configuration Editor" under the "Management" section. From the "Section:" drop-down list at the top of the configuration editor, locate “system.webServer/security/access”. Click on the drop-down list for "sslFlags". Select the "ssl128" check box. Click "Apply" in the "Actions" pane.

Fix Text (F-83549r1_fix)

Follow the procedures below for each site hosted on the IIS 8.5 web server:

Open the IIS 8.5 Manager.

Double-click the "SSL Settings" icon under the "IIS" section.

Select the "Require SSL" setting.

Select the "Client Certificates Required" setting.

Click "Apply" in the "Actions" pane.

Click the site under review.

Under "Configuration Editor" under the "Management" section.

From the "Section:" drop-down list at the top of the configuration editor, locate “system.webServer/security/access”.

Click on the drop-down list for "sslFlags".

Select the "ssl128" check box.

Click "Apply" in the "Actions" pane.