Details

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.

Solution

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

Supportive Information

The following resource is also helpful.

• https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_ASA_STIG.zip

This security hardening control applies to the following category of controls within NIST 800-53: Access Control.This control applies to the following type of system Cisco.

References

• 800-53|AC-4
• CAT|II
• CCI|CCI-001414
• Rule-ID|SV-239960r666286_rule
• STIG-ID|CASA-VN-000300
• Vuln-ID|V-239960

Source

• Tenable.com/audits