Public web servers must use TLS if authentication is required.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-13694	WG342 IIS6	SV-28566r2_rule	ECCT-1 ECCT-2	Medium

Description
TLS encryption is optional for a public web server. However, if authentication and encryption are used, then the use of TLS is required. Transactions encrypted with trusted certificates are necessary when the information being transferred is not intended to be accessed by all parties on the network. To the extent this standard applies, this check is valid for the SIPRNet also. FIPS 140-2 compliance includes: TLS V1.0 or greater TLS must be enabled, the use of SSL disabled Configuration of required cryptographic modules as specified by NIST CVMP

Description

TLS encryption is optional for a public web server. However, if authentication and encryption are used, then the use of TLS is required. Transactions encrypted with trusted certificates are necessary when the information being transferred is not intended to be accessed by all parties on the network. To the extent this standard applies, this check is valid for the SIPRNet also. FIPS 140-2 compliance includes: TLS V1.0 or greater TLS must be enabled, the use of SSL disabled Configuration of required cryptographic modules as specified by NIST CVMP

STIG	Date
IIS6 Site	2011-10-03

Details

Check Text ( C-28835r2_chk )
1. Open the IIS Manager > Right click on the website 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 check boxes are checked. If the Require secure channel (SSL) and Require 128-bit encryption check boxes are not checked, this is a finding. If the site requires SSL and 128-bit encryption, then the version of SSL also needs to be verified. The following registry keys need to exist and be set to not allow anything lower than SSL V3.1 / 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. NOTE: 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 SSL V3.1 / TLS. 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 certificated 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. Users should not have the ability to bypass the content switch to access the web sites.

Check Text ( C-28835r2_chk )

1. Open the IIS Manager > Right click on the website 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 check boxes are checked.

If the Require secure channel (SSL) and Require 128-bit encryption check boxes are not checked, this is a finding.

If the site requires SSL and 128-bit encryption, then the version of SSL also needs to be verified.

The following registry keys need to exist and be set to not allow anything lower than SSL V3.1 / 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.

NOTE: 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 SSL V3.1 / TLS.

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 certificated 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. Users should not have the ability to bypass the content switch to access the web sites.

Fix Text (F-32693r1_fix)
1. Obtain and install a server certificate from a .mil Certificate Authority or approved DoD ECA. 2. Open the IIS Manager > Right click on the website to be examined > Select properties > select the Directory Security tab > Select the Edit button in the Secure communications section. 3. Select Require secure channel (SSL) and Require 128-bit encryption check boxes. 4. Set the version SSL by creating and setting the following registry to not allow anything lower than SSL V3.1 / TLS. Ensure 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 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 SSL V3.1 / TLS.

Fix Text (F-32693r1_fix)

1. Obtain and install a server certificate from a .mil Certificate Authority or approved DoD ECA.
2. Open the IIS Manager > Right click on the website to be examined > Select properties > select the Directory Security tab > Select the Edit button in the Secure communications section.
3. Select Require secure channel (SSL) and Require 128-bit encryption check boxes.
4. Set the version SSL by creating and setting the following registry to not allow anything lower than SSL V3.1 / TLS. Ensure 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

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 SSL V3.1 / TLS.