The IIS 8.5 website session state cookie settings must be configured to Use Cookies mode.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-76777	IISW-SI-000202	SV-91473r2_rule		Medium

Description
When the session information is stored on the client, the session ID, along with the user authorization and identity information, is sent along with each client request and is stored in either a cookie, embedded in the uniform resource locator (URL), or placed in a hidden field on the displayed form. Each of these offers advantages and disadvantages. The biggest disadvantage to all three is the hijacking of a session along with all of the user's credentials. When the user authorization and identity information is stored on the server in a protected and encrypted database, the communication between the client and website will only send the session identifier, and the server can then retrieve user credentials for the session when needed. If, during transmission, the session were to be hijacked, the user's credentials would not be compromised. ASP.NET provides a session state, which is available as the HttpSessionState class, as a method of storing session-specific information that is visible only within the session. ASP.NET session state identifies requests from the same browser during a limited time window as a session, and provides the ability to persist variable values for the duration of that session. Cookies associate session information with client information for the duration of a user’s connection to a website. Using cookies is a more efficient way to track session state than any of the methods that do not use cookies because cookies do not require any redirection.

Description

When the session information is stored on the client, the session ID, along with the user authorization and identity information, is sent along with each client request and is stored in either a cookie, embedded in the uniform resource locator (URL), or placed in a hidden field on the displayed form. Each of these offers advantages and disadvantages. The biggest disadvantage to all three is the hijacking of a session along with all of the user's credentials. When the user authorization and identity information is stored on the server in a protected and encrypted database, the communication between the client and website will only send the session identifier, and the server can then retrieve user credentials for the session when needed. If, during transmission, the session were to be hijacked, the user's credentials would not be compromised. ASP.NET provides a session state, which is available as the HttpSessionState class, as a method of storing session-specific information that is visible only within the session. ASP.NET session state identifies requests from the same browser during a limited time window as a session, and provides the ability to persist variable values for the duration of that session. Cookies associate session information with client information for the duration of a user’s connection to a website. Using cookies is a more efficient way to track session state than any of the methods that do not use cookies because cookies do not require any redirection.

STIG	Date
IIS 8.5 Site Security Technical Implementation Guide	2018-09-18

Details

Check Text ( C-76433r3_chk )
Follow the procedures below for each site hosted on the IIS 8.5 web server: Open the IIS 8.5 Manager. Click the site name. Under the "ASP.NET" section, select "Session State". Under "Cookie Settings", verify the "Use Cookies" mode is selected from the "Mode:" drop-down list. If the "Use Cookies" mode is selected, this is not a finding. Alternative method: Click the site name. Select "Configuration Editor" under the "Management" section. From the "Section:" drop-down list at the top of the configuration editor, locate "system.web/sessionState". Verify the "cookieless" is set to "UseCookies". If the "cookieless" is not set to "UseCookies", this is a finding.

Check Text ( C-76433r3_chk )

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

Open the IIS 8.5 Manager.

Click the site name.

Under the "ASP.NET" section, select "Session State".

Under "Cookie Settings", verify the "Use Cookies" mode is selected from the "Mode:" drop-down list.

If the "Use Cookies" mode is selected, this is not a finding.

Alternative method:

Click the site name.

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

From the "Section:" drop-down list at the top of the configuration editor, locate "system.web/sessionState".

Verify the "cookieless" is set to "UseCookies".

If the "cookieless" is not set to "UseCookies", this is a finding.

Fix Text (F-83473r2_fix)
Follow the procedures below for each site hosted on the IIS 8.5 web server: Open the IIS 8.5 Manager. Click the site name. Under the ASP.NET section, select "Session State". Under "Cookie Settings", select the "Use Cookies" from the "Mode:" drop-down list. Select "Apply" from the "Actions" pane.