| 1. Open the IIS Manager > Right click on the web site to be examined > Select properties > Select the Web Site tab > Note the entry for the SSL port (i.e. 443). |
2. Select the Directory Security tab > Select the Edit button in the Secure communications section.
3. Ensure the Require secure channel (SSL) and Require 128-bit encryption checkboxes are checked.
If the Require secure channel (SSL) and Require 128-bit encryption checkboxes are not checked, this is a finding.
If the site requires SSL and 128-bit encryption, then the version of SSL/TLS also needs to be verified.
The following registry keys need to exist and be set to not allow anything lower than TLS. This can be accomplished by ensuring the following value exists in each of the keys:
Enabled REG_DWORD 0
HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders \SCHANNEL\Protocols\PCT 1.0\Client
HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders \SCHANNEL\Protocols\PCT 1.0\Server
HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders \SCHANNEL\Protocols\SSL 2.0\Client
HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders \SCHANNEL\Protocols\SSL 2.0\Server
HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders \SCHANNEL\Protocols\SSL 3.0\Client
HKey_Local_Machine\System\CurrentControlSet\Control\SecurityProviders \SCHANNEL\Protocols\SSL 3.0\Server
If these keys are not set to a DWORD value of 0, this is a finding.
If the keys do not contain the value "Enabled", this would also be a finding.
The keys for TLS 1.0 do not require the Enabled value to be present, but if it is, it needs to be set to REG_DWORD 1, to enable TLS. If the "Enabled" value is present and set to 0, this is a finding.
NOTE: In some cases the web servers are configured in an environment to support load balancing. This configuration most likely utilizes a content switch to control traffic to the various web servers. In this situation, the SSL certificate for the web sites may be installed on the content switch vs. the individual web sites. This solution is acceptable as long as the web servers are isolated from the general population LAN. We do not want users to have the ability to bypass the content switch to access the web sites.