The Apache web server must perform RFC 5280-compliant certification path validation.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-92517	AS24-W2-000380	SV-102605r1_rule		Medium

Description
A certificate's certification path is the path from the end entity certificate to a trusted root certification authority (CA). Certification path validation is necessary for a relying party to make an informed decision regarding acceptance of an end entity certificate. Certification path validation includes checks such as certificate issuer trust, time validity, and revocation status for each certificate in the certification path. Revocation status information for CA and subject certificates in a certification path is commonly provided via certificate revocation lists (CRLs) or online certificate status protocol (OCSP) responses.

Description

A certificate's certification path is the path from the end entity certificate to a trusted root certification authority (CA). Certification path validation is necessary for a relying party to make an informed decision regarding acceptance of an end entity certificate. Certification path validation includes checks such as certificate issuer trust, time validity, and revocation status for each certificate in the certification path. Revocation status information for CA and subject certificates in a certification path is commonly provided via certificate revocation lists (CRLs) or online certificate status protocol (OCSP) responses.

STIG	Date
Apache Server 2.4 Windows Site Security Technical Implementation Guide	2019-12-19

Details

Check Text ( C-91819r1_chk )
Review the <'INSTALLED PATH'>\conf\httpd.conf file to determine if the "SSLVerifyClient" and "SSLVerifyDepth" directives exist and look like the following. If they do not, this is a finding. SSLVerifyClient require SSLVerifyDepth 1 If "SSLVerifyDepth" is set to "0", this is a finding.

Fix Text (F-98759r1_fix)
Ensure that client verification is enabled. For each enabled hosted application on the server, enable and set "SSLVerifyClient" to "require" and ensure that the server is configured to verify the client certificate by enabling "SSLVerifyDepth". Example: SSLVerifyClient require Find the line "SSLVerifyDepth" and ensure it is set properly: SSLVerifyDepth 1 "SSLVerifyDepth" is set based on the number of CAs that are required in the certificate chain to check, before the client certificate is accepted as valid. A setting of "0" would allow self-signed CAs to validate client certificates, which is not desirable in this context. Additional Information: https://httpd.apache.org/docs/current/mod/mod_ssl.html

Fix Text (F-98759r1_fix)

Ensure that client verification is enabled. For each enabled hosted application on the server, enable and set "SSLVerifyClient" to "require" and ensure that the server is configured to verify the client certificate by enabling "SSLVerifyDepth".

Example:

SSLVerifyClient require

Find the line "SSLVerifyDepth" and ensure it is set properly:

SSLVerifyDepth 1

"SSLVerifyDepth" is set based on the number of CAs that are required in the certificate chain to check, before the client certificate is accepted as valid. A setting of "0" would allow self-signed CAs to validate client certificates, which is not desirable in this context.

Additional Information:

https://httpd.apache.org/docs/current/mod/mod_ssl.html