jeffwNovel attack against virtually all VPN apps neuters their entire purpose
RaoulDookSo if they are changing routes by using DHCP options, perhaps this could be exploited by telecom insiders when you are using mobile data, because your mobile data IP could be assigned by a DHCP server on the telecom network. If you’re at home on wifi, then you can control your own DHCP server to prevent that.
RimuNo - the VPN provider has another DHCP server for use 'inside' the VPN.
SzethFriendOfNimiExcept this bypasses that I believe.
The attack vector described in the article uses the VPN client machine's host network, i.e. the local network the device is attached to. They don't discuss the DHCP server of the VPN provider.
Read this part more carefully:
By pushing routes that are more specific than a /0 CIDR range that most VPNs use, we can make routing rules that have a higher priority than the routes for the virtual interface the VPN creates.
Most traffic gets sent through a VPN only because of the default gateway (set by the VPN) in the client’s routing table. If the client’s ISP were to have their DHCP server set one or more specific routes that are broad enough to cover most of the address space, they would effectively override that default gateway. I believe that’s the scenario described in the article.
Max-PMost VPN providers don’t use DHCP. OpenVPN emulates and hooks DHCP requests client-side to hand the OS the IP it got over the OpenVPN protocol in a more standard way (unless you use Layer 2 tunnels which VPN providers don’t because it’s useless for that use case). WireGuard doesn’t support DHCP at all and it always comes from configuration.