Title

The Cisco ASA VPN gateway must be configured to restrict what traffic is transported via the IPsec tunnel according to flow control policies. (Cat II impact)

Discussion

Unrestricted traffic may contain malicious traffic which poses a threat to an enclave or to other connected networks. Additionally, unrestricted traffic may transit a network, which uses bandwidth and other resources. VPN traffic received from another enclave with different security policy or level of trust must not bypass being inspected by the firewall before being forwarded to the private network.

Check Content

Step 1: Determine the ACL that is used to define what traffic will be transported via the IPsec tunnel. crypto map IPSEC_MAP 10 match address SITE1_SITE2 crypto map IPSEC_MAP 10 set peer x.x.x.x Step 2: Verify that the traffic defined in the ACL is in accordance with flow control policies. access-list SITE1_SITE2 extended permit ip 192.168.1.0 255.255.255.0 192.168.2.0 255.255.255.0 If the VPN gateway is not configured to restrict what traffic is transported via the IPsec tunnel, this is a finding.

Fix Text

Step 1: Define what traffic will be transported via the IPsec tunnel as shown in the example below. ASA1(config)# access-list SITE1_SITE2 extended permit ip 192.168.1.0 255.255.255.0 192.168.2.0 255.255.255.0 Step 2: Apply the ACL to the IPsec crypto map. ASA1(config)# crypto map IPSEC_MAP 10 match address SITE1_SITE2

Additional Identifiers

Rule ID: SV-239960r666286_rule

Vulnerability ID: V-239960

Group Title: SRG-NET-000019-VPN-000040

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.