The IIS 10.0 web server must enable HTTP Strict Transport Security (HSTS).

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-218827	IIST-SV-000205	SV-218827r810855_rule		Low

Description
HTTP Strict Transport Security (HSTS) ensures browsers always connect to a website over TLS. HSTS exists to remove the need for redirection configurations. HSTS relies on the browser, web server, and a public "Allowlist". If the browser does not support HSTS, it will be ignored.

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

Details

Check Text ( C-20299r810854_chk )
Access the IIS 10.0 Web Server. Open IIS Manager. Click the IIS 10.0 web server name. Open on Configuration Editor under Management. For the Section, navigate to system.applicationHost/sites. Expand siteDefaults and HSTS. If enabled is not set to True, this is a finding. If includeSubDomains is not set to True, this is a finding. If max-age is not set to a value greater than 0, this is a finding. If redirectHttpToHttps is not True, this is a finding. If the website is behind a load balancer or proxy server, and HSTS enablement is handled there, this is Not Applicable. If the version of Windows Server does not natively support HSTS, this is not a finding.

Check Text ( C-20299r810854_chk )

Access the IIS 10.0 Web Server.
Open IIS Manager.
Click the IIS 10.0 web server name.
Open on Configuration Editor under Management.
For the Section, navigate to system.applicationHost/sites.
Expand siteDefaults and HSTS.
If enabled is not set to True, this is a finding.
If includeSubDomains is not set to True, this is a finding.
If max-age is not set to a value greater than 0, this is a finding.
If redirectHttpToHttps is not True, this is a finding.

If the website is behind a load balancer or proxy server, and HSTS enablement is handled there, this is Not Applicable.

If the version of Windows Server does not natively support HSTS, this is not a finding.

Fix Text (F-20297r802885_fix)
Using the Configuration Editor in the IIS Manager or Powershell: Enable HSTS. Set includeSubDomains to True. Set max-age to a value greater than 0. Set redirectHttpToHttps to True.