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

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-218826	SRG-APP-000001-WSR-000001	IIST-SV-000200	SV-218826r960735_rule	2025-02-11	3

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).

ℹ️ Check
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.

ℹ️ Check

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
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.