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).
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.