Public web servers must use TLS if authentication is required.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-13694	WG342 A22	SV-33030r2_rule		Medium

Description
Transport Layer Security (TLS) is optional for a public web server. However, if authentication is being performed, then the use of the TLS protocol is required. Without the use of TLS, the authentication data would be transmitted unencrypted and would become vulnerable to disclosure. Using TLS along with DoD PKI certificates for encryption of the authentication data protects the information from being accessed by all parties on the network. To further protect the authentication data, the web server must use a FIPS 140-2 approved TLS version and all non-FIPS-approved SSL versions must be disabled. FIPS 140-2 approved TLS versions include TLS V1.0 or greater. NIST SP 800-52 specifies the preferred configurations for government systems.

Description

Transport Layer Security (TLS) is optional for a public web server. However, if authentication is being performed, then the use of the TLS protocol is required. Without the use of TLS, the authentication data would be transmitted unencrypted and would become vulnerable to disclosure. Using TLS along with DoD PKI certificates for encryption of the authentication data protects the information from being accessed by all parties on the network. To further protect the authentication data, the web server must use a FIPS 140-2 approved TLS version and all non-FIPS-approved SSL versions must be disabled. FIPS 140-2 approved TLS versions include TLS V1.0 or greater. NIST SP 800-52 specifies the preferred configurations for government systems.

STIG	Date
APACHE 2.2 Site for UNIX Security Technical Implementation Guide	2019-01-07

Details

Check Text ( C-33713r3_chk )
Enter the following command: /usr/local/apache2/bin/httpd –M This will provide a list of all the loaded modules. Verify that the “ssl_module” is loaded. If this module is not found, this is a finding. After determining that the ssl module is active, enter the following command: grep "SSL" /usr/local/apache2/conf/httpd.conf Review the SSL sections of the httpd.conf file, all enabled SSLProtocol directives for Apache 2.2.22 and older must be set to “TLSv1”. Releases newer than Apache 2.2.22 must be set to "ALL -SSLv2 -SSLv3". If SSLProtocol is not set to the proper value, this is a finding. All enabled SSLEngine directives must be set to “on”, If they are not, this a finding. NOTE: In some cases 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 TLS 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. Users should not have the ability to bypass the content switch to access the web sites.

Check Text ( C-33713r3_chk )

Enter the following command:

/usr/local/apache2/bin/httpd –M

This will provide a list of all the loaded modules. Verify that the “ssl_module” is loaded. If this module is not found, this is a finding.

After determining that the ssl module is active, enter the following command:

grep "SSL" /usr/local/apache2/conf/httpd.conf

Review the SSL sections of the httpd.conf file, all enabled SSLProtocol directives for Apache 2.2.22 and older must be set to “TLSv1”. Releases newer than Apache 2.2.22 must be set to "ALL -SSLv2 -SSLv3". If SSLProtocol is not set to the proper value, this is a finding.

All enabled SSLEngine directives must be set to “on”, If they are not, this a finding.

NOTE: In some cases 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 TLS 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. Users should not have the ability to bypass the content switch to access the web sites.

Fix Text (F-29345r2_fix)
Edit the httpd.conf file and set the SSLProtocol to "TLSv1" for Apache 2.2.22 and older or to "ALL -SSLv2 -SSLv3" for Apache versions newer than 2.2.22. The SSLEngine parameter must also be set to On.