Privacy

31978 readers

405 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

Posting a link to a website containing tracking isn't great, if contents of the website are behind a paywall maybe copy them into the post
Don't promote proprietary software
Try to keep things on topic
If you have a question, please try searching for previous discussions, maybe it has already been answered
Reposts are fine, but should have at least a couple of weeks in between so that the post can reach a new audience
Be nice :)

Related communities

Chat rooms

[Matrix/Element]Dead
Discord

much thanks to @gary_host_laptop for the logo design :)

founded 5 years ago

MODERATORS

Novel attack against virtually all VPN apps neuters their entire purpose (arstechnica.com)

submitted 6 months 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.

you are viewing a single comment's thread
view the rest of the comments

[–] Slotos@feddit.nl 37 points 6 months ago (1 children)

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 6 months ago* (last edited 6 months ago) (1 children)

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 6 months ago* (last edited 6 months ago) (1 children)

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 6 months ago

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