Interesting. I was all ready to ask how having a malicious DHCP server would matter if VPNs also use DHCP to give a client a VPN IP, but I didn’t know DHCP could do more than just hand out IPs.
So long as you keep all of your traffic encrypted, no one’ll be able to snoop on it, though they could already see destinations/type of traffic. Anyone who controls a VPN start or end point can see anything that tcpdump can reveal.
Which is ironically one of the primary reasons you’d want to use a VPN. Public WiFi? VPN, to prevent MITM attacks from a spoofed router. Work WiFi on your personal device? VPN, to prevent your employer from spying on your browsing habits during your break time.
It is all interesting, but most core network services are jointed at the hip. If you can tamper with one service, you can usually fuck with all of them. Also, DHCP is much more than “gimmie an IP address”. It’s kinda always been a way to configure almost anything at layer 3 on a host OS.
Calling this an exploit is a bit of a stretch and why they focused on VPN bypass is kind of ‘meh’ compared to all the rest of the things you could do If you control the routing tables on a client. Hell, if you control DHCP, you control client DNS as well, so that could be fun to abuse too.
This kind of report is almost like saying ‘rm -rf’ is an exploit after you give someone root access.
Edit: This is a coffee-shop’ish type of attack. I am aware of that.
Add comment