The IIS 10.0 websites MaxConnections setting must be configured to limit the number of allowed simultaneous session requests.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-218826	IIST-SV-000200	SV-218826r561041_rule		Medium

Description
Resource exhaustion can occur when an unlimited number of concurrent requests are allowed on a website, facilitating a Denial of Service (DoS) attack. Mitigating this kind of attack will include limiting the number of concurrent HTTP/HTTPS requests per IP address and may include, where feasible, limiting parameter values associated with keepalive (i.e., a parameter used to limit the amount of time a connection may be inactive).

Description

Resource exhaustion can occur when an unlimited number of concurrent requests are allowed on a website, facilitating a Denial of Service (DoS) attack. Mitigating this kind of attack will include limiting the number of concurrent HTTP/HTTPS requests per IP address and may include, where feasible, limiting parameter values associated with keepalive (i.e., a parameter used to limit the amount of time a connection may be inactive).

STIG	Date
Microsoft IIS 10.0 Server Security Technical Implementation Guide	2020-09-25

Details

Check Text ( C-20298r310953_chk )
Access the IIS 10.0 IIS Manager. Click the IIS 10.0 server. Select "Configuration Editor" under the "Management" section. From the "Section:" drop-down list at the top of the configuration editor, locate "system.applicationHost/sites". Expand "siteDefaults". Expand "limits". Review the results and verify the value is greater than zero for the "maxconnections" parameter. If the maxconnections parameter is set to zero, this is a finding.

Check Text ( C-20298r310953_chk )

Access the IIS 10.0 IIS Manager.

Click the IIS 10.0 server.

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

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

Expand "siteDefaults".
Expand "limits".

Review the results and verify the value is greater than zero for the "maxconnections" parameter.

If the maxconnections parameter is set to zero, this is a finding.

Fix Text (F-20296r310954_fix)
Access the IIS 10.0 IIS Manager. Click the IIS 10.0 server. Select "Configuration Editor" under the "Management" section. From the "Section:" drop-down list at the top of the configuration editor, locate "system.applicationHost/sites". Expand "siteDefaults". Expand "limits". Set the "maxconnections" parameter to a value greater than zero.