67
Novel attack against virtually all VPN apps neuters their entire purpose (arstechnica.com)
submitted 1 week ago by 0xtero@beehaw.org to c/privacy@lemmy.ml
11 comments fedilink hide all child comments

Pulling this off requires high privileges in the network, so if this is done by intruder you're probably having a Really Bad Day anyway, but might be good to know if you're connecting to untrusted networks (public wifi etc). For now, if you need to be sure, either tether to Android - since the Android stack doesn't implement DHCP option 121 or run VPN in VM that isn't bridged.

top 11 comments
sorted by: hot top controversial new old
[-] Slotos@feddit.nl 37 points 1 week ago

Control of the DHCP server in the victim’s network is required for the attack to work.

This is not a VPN vulnerability, but a lower level networking setup manipulation that negates naive VPN setups by instructing your OS to send traffic outside of VPN tunnel.

In conclusion, if your VPN setup doesn’t include routing guards or an indirection layer, ISP controlled routers and public WiFis will make you drop out of the tunnel now that there’s a simple video instruction out there.

[-] ArcaneSlime@lemmy.dbzer0.com 4 points 1 week ago* (last edited 1 week ago)

Do we know which VPNs do have routing guards or an indirection layer? Especially out of the "good" ones; mullvad, proton, air, and IVPN?

[-] NeuronautML@lemmy.ml 6 points 1 week ago* (last edited 1 week ago)

Mullvad has written a post about it Here.

FYI

The desktop versions (Windows, macOS and Linux) of Mullvad's VPN app have firewall rules in place to block any traffic to public IPs outside the VPN tunnel. These effectively prevent both LocalNet and TunnelVision from allowing the attacker to get hold of plaintext traffic from the victim.

Android is not vulnerable to TunnelVision simply because it does not implement DHCP option 121, as explained in the original article about TunnelVision.

iOS is unfortunately vulnerable to TunnelVision, for the same reason it is vulnerable to LocalNet, as we outlined in our blog post about TunnelCrack. The fix for TunnelVision is probably the same as for LocalNet, but we have not yet been able to integrate and ship that to production.

I gotta say, i am really impressed with Mullvad. They're not just a VPN seller. They write security compromise bulletins regularly and as soon as vulnerabilities show up and they actively lobby at the EU organs for more privacy laws. They really work and live their identity in every way.

[-] ArcaneSlime@lemmy.dbzer0.com 4 points 1 week ago

Damn I might have to go back to them. I just want port forwarding, is that so much to ask?!

[-] narc0tic_bird@lemm.ee 30 points 1 week ago

The title is misleading in that the attack isn't against the VPN apps or even the VPN protocols, but against the networking stack of the operating system.

I also don't get much value out of the statement that "every" OS except Android is vulnerable. Do they really mean all other OSes, or just what would come to mind for most people, i.e. Windows, macOS, Linux, iOS? What about the various BSDs for example?

[-] 0xtero@beehaw.org 14 points 1 week ago* (last edited 1 week ago)

I also don’t get much value out of the statement that “every” OS except Android is vulnerable. Do they really mean all other OSes, or just what would come to mind for most people, i.e. Windows, macOS, Linux, iOS? What about the various BSDs for example?

It's a DHCP manipulation attack, so every RFC 3442 compliant DHCP implementation implementing option 121 would be "vulnerable" (it's not vulnerability though). Android apparently doesn't implement it, so it's technically impossible to pull off against Android device. There might be others, but I'd guess most serious server/desktop OS'es implement it.

The title isn't misleading at all, even though the "neutering their entire purpose" is a bit of a click-bait. This doesn't affect ingress VPN at all.

It's an attack that uses DHCP features (according to RFC).

It's a clever way to uncloak egress VPN users, therefore it does have privacy impact since most of us use VPN for purposes of hiding out traffic from the local network and provider and there's no "easy" fix since it's just a clever use of existing RFC.

[-] floofloof@lemmy.ca 4 points 1 week ago

Slightly off topic, but it turns out Android has a different VPN vulnerability:

https://mullvad.net/en/blog/dns-traffic-can-leak-outside-the-vpn-tunnel-on-android

[-] krolden@lemmy.ml 2 points 1 week ago

Only if you dont have tunnel dns configured

[-] delirious_owl@discuss.online 1 points 1 week ago

Its only half of the systems that are affected lol

[-] yogthos@lemmy.ml 1 points 1 week ago

I thought the entire purpose was to watch content that region locked?

[-] PowerCrazy@lemmy.ml 1 points 1 week ago

And also bittorrent.

this post was submitted on 07 May 2024
67 points (98.6% liked)

Privacy

29157 readers
445 users here now

A place to discuss privacy and freedom in the digital world.

Privacy has become a very important issue in modern society, with companies and governments constantly abusing their power, more and more people are waking up to the importance of digital privacy.

In this community everyone is welcome to post links and discuss topics related to privacy.

Some Rules

Related communities

Chat rooms

much thanks to @gary_host_laptop for the logo design :)

founded 4 years ago
MODERATORS
k_o_t@lemmy.ml
tmpod@lemmy.pt
TheAnonymouseJoker@lemmy.ml
Yayannick@lemmy.ml
ranok@sopuli.xyz