TunnelVision - decloaking VPNs using DHCP
A new decloaking technique for nearly all VPN implementations has been found, which allows attackers to inject entries into the routing tables of unsuspecting victims using DHCP option 121. This allows attackers to redirect traffic, which is supposed to be sent encrypted over the VPN, through the physical interface handling DHCP for the network the victim's computer is connected to, effectively bypassing the VPN connection.