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[-] xabadak@lemmings.world 1 points 5 months ago

No worries, and thanks for providing a response nonetheless. I'll look into your suggestion when I have the time. The official Wireguard website also had some guide on network namespaces here but afaik it didn't explain how to set it up persistently

[-] xabadak@lemmings.world 1 points 5 months ago

I see what you mean now. I wouldn't advocate for people to disable DHCP features either. It should be the VPN provider's responsibility to provide a proper VPN client that mitigates attacks like these.

[-] xabadak@lemmings.world 2 points 5 months ago

Yeah TOR is an example of a mixnet. WHat I was talking about was a combination of your Scenario A and Scenario B, where you have a mixnet where everybody's traffic goes through multiple proxies, and many people are using each proxy, and you have padding and timing added to make sure traffic flows are consistent. As far as trusting nodes, you have to do that regardless of your set up. If you don't use any VPN, you have to trust your ISP. If you use a VPN like Mullvad, you have to trust Mullvad. If you use a mixnet, you have to trust that all your chosen proxies aren't colluding. So like you said, it's up to your own judgement and threat model.

[-] xabadak@lemmings.world 1 points 5 months ago

why is a split tunnel relevant? I thought all VPNs are vulnerable unless they use a firewall like I do, or network namespaces.

At least the way I understand it, a normal VPN redirects your internet traffic to instead go through a virtual network interface, which then encrypts and sends your traffic through the VPN. This attack uses a malicious DHCP server to inject routes into your system, redirecting traffic to the attacker instead of towards the virtual network interface.

[-] xabadak@lemmings.world 1 points 5 months ago

Hypothetically, what if everybody in the world were using mixnets to obfuscate destination/origin, and then mullvad's DAITA to obfuscate traffic timing and size. Would netflow analysis be able to defeat that?

[-] xabadak@lemmings.world 2 points 5 months ago

It all depends on how much you trust the devices on your LAN. So your ISP can't do anything unless they own and control your router, since that is on your LAN. So one concern might be if you connect your PC to coffee shop wifi, since all other devices in the shop are on the same LAN, not to mention the coffee shop owns the wifi router and can also perform the attack. Another concern might be if a family member in your house has a device that got hacked, then all devices in your house are vulnerable.

[-] xabadak@lemmings.world 1 points 5 months ago

how would you not use DHCP when connecting to coffee shop wifi?

[-] xabadak@lemmings.world 2 points 5 months ago

I think you both are talking past each other. You said "But if nobody else is using those same endpoints." but @MigratingtoLemmy@lemmy.world said "There’s plenty of people who are going to be renting VPSes and will have their traffic originate from the same IP range as mine". Reading this thread, it seems like you both have different network setups in mind.

[-] xabadak@lemmings.world 1 points 5 months ago

Do you know how to make it so all the host's traffic is sent through the VPN namespace? I couldn't figure out how to do this so I ended up just writing my own firewall. Network namespaces seems like a better solution.

[-] xabadak@lemmings.world 2 points 5 months ago

I saw that but unfortunately it doesn't detail how to set it up persistently on every boot. And I also haven't seen anybody using this method, probably because of the lack of tooling around it. For example afaik the official Mullvad client on linux just uses a firewall.

[-] xabadak@lemmings.world 2 points 5 months ago

Using untrusted networks is quite common, like coffee shop wifi or airport wifi.

[-] xabadak@lemmings.world 2 points 5 months ago

what features are you talking about?

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submitted 5 months ago by xabadak@lemmings.world to c/linux@lemmy.ml

In light of the recent TunnelVision vulnerability I wanted to share a simple firewall that I wrote for wireguard VPNs.

https://codeberg.org/xabadak/wg-lockdown

If you use a fancy official VPN client from Mullvad, PIA, etc, you won't need this since most clients already have a kill switch built in (also called Lockdown Mode in Mullvad). This is if you use a barebones wireguard VPN like me, or if your VPN client has a poorly-designed kill switch (like NordVPN, more info here).

A firewall should mitigate the vulnerability, though it does create a side-channel that can be exploited in extremely unlikely circumstances, so a better solution would be to use network namespaces (more info here). Unfortunately I'm a noob and I couldn't find any scripts or tools to do it that way.

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xabadak

joined 5 months ago