F5BI-AP-300161 - The F5 BIG-IP appliance providing remote access intermediary services must disable split-tunneling for remote clients' VPNs.

Information

Split tunneling would in effect allow unauthorized external connections, making the system more vulnerable to attack and to exfiltration of organizational information.

A VPN hardware or software client with split tunneling enabled provides an unsecured backdoor to the enclave from the internet. With split tunneling enabled, a remote client has access to the internet while at the same time has established a secured path to the enclave via an IPsec tunnel. A remote client connected to the internet that has been compromised by an attacker on the internet, provides an attack base to the enclave's private network via the IPsec tunnel. Hence, it is imperative that the VPN gateway enforces a no split-tunneling policy to all remote clients.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

Obtain the Network Access name in the Access Profile:
From the BIG-IP GUI:
1. Access.
2. Profiles/Policies.
3. Access Profiles.
4. Click the name of the Access Profile.
5. Click the Access Policy tab and note the name(s) of the Network Access listed.

Configure the Network Access List:
From the BIG-IP GUI:
1. Access.
2. Connectivity/VPN.
3. Network Access (VPN).
4. Network Access Lists.
5. Click on the Name of the Network Access List.
6. Network Settings tab.
7. Select "Force all traffic through tunnel" under Client Settings >> Traffic Options.
8. Click "Update".

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_F5_BIG-IP_TMOS_Y25M07_STIG.zip

Item Details

Category: CONFIGURATION MANAGEMENT, SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|CM-6b., 800-53|SC-7(7), CAT|II, CCI|CCI-000366, CCI|CCI-002397, Rule-ID|SV-266172r1024404_rule, STIG-ID|F5BI-AP-300161, Vuln-ID|V-266172

Plugin: F5

Control ID: c534b9d0f950798ca6a27d589f80c7a91a95efe3fdb54c76dc35f08681f1d522