The VPN gateway must not accept certificates that have been revoked when using PKI for authentication.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-30947	NET-VPN-050	SV-40989r1_rule	ECSC-1	Medium

Description
Situations may arise in which the certificate issued by a Certificate Authority (CA) may need to be revoked before the lifetime of the certificate expires. For example, the certificate is known to have been compromised. To achieve this, a list of certificates that have been revoked, known as a Certificate Revocation List (CRL), is sent periodically from the CA to the IPSec gateway. When an incoming Internet Key Exchange (IKE) session is initiated for a remote client or peer whose certificate is revoked, the CRL will be checked to see if the certificate is valid; if the certificate is revoked, IKE will fail and an IPSec security association will not be established for the remote end-point.

Description

Situations may arise in which the certificate issued by a Certificate Authority (CA) may need to be revoked before the lifetime of the certificate expires. For example, the certificate is known to have been compromised. To achieve this, a list of certificates that have been revoked, known as a Certificate Revocation List (CRL), is sent periodically from the CA to the IPSec gateway. When an incoming Internet Key Exchange (IKE) session is initiated for a remote client or peer whose certificate is revoked, the CRL will be checked to see if the certificate is valid; if the certificate is revoked, IKE will fail and an IPSec security association will not be established for the remote end-point.

STIG	Date
IPSec VPN Gateway Security Technical Implementation Guide	2018-03-08

Details

Check Text ( C-39608r1_chk )
Examine the CA trust point defined on the VPN gateway to determine if it references a CRL and that revocation check has been enabled. An alternate mechanism for checking the validity of a certificate is the use of the Online Certificate Status Protocol (OCSP). Unlike CRLs, which provide only periodic certificate status checks, OCSP can provide timely information regarding the status of a certificate.

Check Text ( C-39608r1_chk )

Examine the CA trust point defined on the VPN gateway to determine if it references a CRL and that revocation check has been enabled. An alternate mechanism for checking the validity of a certificate is the use of the Online Certificate Status Protocol (OCSP). Unlike CRLs, which provide only periodic certificate status checks, OCSP can provide timely information regarding the status of a certificate.

Fix Text (F-34758r1_fix)
Configure the CA trust point to enable certificate revocation check by referencing a CRL or via OCSP.