creating split tunnel on full tunnel enforcement

andrew.jeon — Thu, 22 Jul 2021 16:52:04 GMT

We’ve recently discovered that the Mac GlobalProtect client does not terminate existing network connections after full tunnel with no access to local network is established. This is reproducible In the following procedure:

Disconnect from VPN
Connect to resource that you should be unable to while connected to GlobalProtect – the connection must be kept alive by software (local RDP/SSH/etc, high port service that would be blocked by Palo, etc)
Connect to GlobalProtect VPN
Connection to resource will be maintained (this will survive multiple connects/disconnects)

In practice, this allows one to create a split tunnel. We’ve had several folks test this by RDPing into a system on their home network, and being able to continue to control the system after the VPN connection is established. There is no “reconnect”, it appears to be uninterrupted. Other VPN solutions like Anyconnect, Pulse secure (both full tunnel with no access to local network) successfully terminate existing connection. This is a security concern as this would be usable as a covert C2 channel.

Does anyone have any suggestions on terminating existing connection on Mac?

Re: creating split tunnel on full tunnel enforcement

Remo — Sun, 25 Jul 2021 11:14:38 GMT

Hi @andrew.jeon

In my opinion, allowing the users to manually connect and disconnect is the actual security concern.

But I understand the issue and I don't know exactly if this is "expected behavior" or a bug. To clarify this you should create a TAC case and ask support/engineering about this one.

topic Re: creating split tunnel on full tunnel enforcement in GlobalProtect Discussions

creating split tunnel on full tunnel enforcement

Re: creating split tunnel on full tunnel enforcement