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Mullvad: Diskless infrastructure using stboot in beta

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Re: Mullvad: Diskless infrastructure using stboot in beta

#31

Post by kfreds »

cmeacham98 wrote: post #17
oefrha wrote: post #10

For people wondering how the hell a user can audit the server is diskless or whatever, the goal appears to be using TPM to provide remote attestation for all code in the boot path. See https://www.system-transparency.org/ .

I hate to be this skeptical, but let's say this is 100% possible (I have my doubts, see previous attacks on things like TPMs and SGX, but I digress). You probably could get 90% of the logging capability by putting monitoring in front of and behind the server, and associating connections by traffic/time. It just seems like this goal of using technology to prove they're trustworthy is unlikely to actually work for a VP…

You are correct that System Transparency is not a universal remedy for all threat models. Indeed the word "secure" is undefined until you have a threat model. Most threat models are implied and undocumented assumptions.

At some stage in an R&D project one should shift from exploration to threat model-driven development. Most people, myself included, tend to focus on technical solutions, and argue back and forth how "oh, but it can be broken using X".

System Transparency aims to provide remote auditability assuming (1) the server hardware specification is correct, (2) a correct cryptographic hash of the contents of the SPI flash containing the platform firmware, and (3) a keypair generated on and only accessible to the platform. This is very simplified of course.

An attacker aiming to tap incoming and outgoing network traffic from our servers, who has physical access to the VPN server's Ethernet port, or an upstream router, isn't in the scope of System Transparency to protect against. We need to use other means for that.

Re: Mullvad: Diskless infrastructure using stboot in beta

#32

Post by azalemeth »

cmeacham98 wrote: post #17
oefrha wrote: post #10

For people wondering how the hell a user can audit the server is diskless or whatever, the goal appears to be using TPM to provide remote attestation for all code in the boot path. See https://www.system-transparency.org/ .

I hate to be this skeptical, but let's say this is 100% possible (I have my doubts, see previous attacks on things like TPMs and SGX, but I digress). You probably could get 90% of the logging capability by putting monitoring in front of and behind the server, and associating connections by traffic/time. It just seems like this goal of using technology to prove they're trustworthy is unlikely to actually work for a VP…

Traffic analysis and correlation analysis is indeed a powerful tool, and in general only communicating at a constant bandwidth between all nodes at all times is the only way to completely defeat it (which is what, I understand, some military systems do). That's inherently highly wasteful, however.

To get around this, Mullvad offer very transparent comprehensive multi-hop routing systems [1]; you can bounce your wireguard tunnels around in layered wireguard tunnels (a bit á-la tor) by just choosing a series of ports to tunnel on and to. My understanding is that each one of these adds non-deterministic latency to your connection and probably would help to make such attacks harder at the very least, because from the point of view of an "all seeing" adversary the fact that all of these servers talk to each other all the time makes it very much harder to know where any packet could have gone. Yes, you can see each individual link but the metadata is lost.

I signed up for Mullvad when the UK's Snooper's Charter came into force and the local health inspectors suddenly had the rights to see my DNS record. Since then, I've had it installed on my router and just route everything through a custom wireguard (originally openvpn) tunnel. I've had some issues with my ISP randomly bandwidth limiting traffic on the odd port to 1 MByte/s, but frankly that makes me more inclined to put everything behind an encrypted tunnel. I don't want my ISP to do traffic shaping and I do want them to just leave me alone and let me communicate in peace. I have absolutely nothing to hide, but now have to accept that I partly live in a country where everything is surveilled all the time, and warantless, unaccountable investigation of my (highly personal!) online habits may be happening. I think Mullvad's excellent product, sensible architecture and reasonable price is worth paying. I'm an academic, unlikely to be of interest to three-letter acronyms, and therefore it matches my needs very well.

[1] https://mullvad.net/en/help/multihop-wireguard/

Re: Mullvad: Diskless infrastructure using stboot in beta

#33

Post by Terry_Roll »

burnaway wrote: post #13
pilif wrote: post #4

Earlier quoted context omitted.

if only there was any proof of this actually being the case and there not being some "accidental" debug log enabled, or some other network level component having "accidental" access to the keys. There's just no good answer to perfect trust-no-one private internet access. If you need to hide all of your traffic from other users in your local network, you can accomplish that in a trust-no-one fashion by running your ow…

>> If you need to hide all of your traffic from other users in your local network, you can accomplish that in a trust-no-one fashion by running your own VPN endpoint on a server you control which provides better privacy guarantees compared to a centralised commercial VPN whose business model will eventually involve selling your data (once user growth stops but shareholders demand continued revenue growth). the privac…

>ie. large number of users sharing the same IP and protects against correlation attacks

Depending on where you are based in the world (see https://www.submarinecablemap.com) realtime throttling of vpn traffic can still identify a user and where they are going in some cases.

You can get a degree of privacy from visiting websites located on servers in big data centres, but nothing a search warrant couldnt find out retrospectively.

Just traceroute your journey inside a vpn to see where abouts you are going when connecting to a webserver anywhere in the world and workout the physical route you are travelling on the cable map.

Obviously the number of languages you speak also restricts where in the world you will be going online to a point and timezones can also make you stand out like a sore thumb if you visit a website when the locals generally arent.

I've identified (US) websites which can workout what DNS server you are using, so in my case, based in the UK if I swap from using a UK ISP dns to using another dns like quad9 in Germany, the (US) websites alter the content you can see, just on that single DNS server change.

There is no privacy!

Re: Mullvad: Diskless infrastructure using stboot in beta

#34

Post by kfreds »

Gigachad wrote: post #20
sanxiyn wrote: post #19

Earlier quoted context omitted.

We assume it is, just like we assume CPU works as advertised. In other words, TPM is part of TCB.

So what is the point? I already assume the code on their server is not malicious by using it. What extra trust does an untrusted TPM chip give me?

System Transparency reduces your trust assumptions on us. As a VPN provider we are in an immense position of power over you. We aim to reduce your trust assumptions on us to a few things that we would need to explicitly lie about in order to betray you.

As an example, let's say that we offered any of our users to at any time during the year show up at our office and inspect our VPN hardware, without warning us beforehand. In that situation, if we wanted to betray your trust and privacy, we would need to put in a lot more effort than if we said "We have secure servers. Trust us on that. No you can't see them.". Does that make sense?

Re: Mullvad: Diskless infrastructure using stboot in beta

#35

Post by dtx1 »

jack_pp wrote: post #28
dtx1 wrote: post #18

Earlier quoted context omitted.

> If you need to hide all of your traffic from other users in your local network, you can accomplish that in a trust-no-one fashion by running your own VPN endpoint on a server you control which provides better privacy guarantees compared to a centralised commercial VPN whose business model will eventually involve selling your data (once user growth stops but shareholders demand continued revenue growth). Well not re…

Do you actually pirate music or did you give it as a general example? I feel no need to pirate music today with all the music streaming services especially since I can find all the music I want on all the streaming services which is a world of difference compared to the video streaming services

I stopped pirating music a while ago when spotify became better than what the trackers i was on delivered. That being said, i have recently started looking into it again since spotify is dragging their asses on high quality streaming and their app support on linux started to annoy me. The alternative streaming services barely support linux at all so they aren't really an alternative for me. But you are right it's mostly tv-shows and movies, a few books here and there. It seems I've basically missed the golden age of netflix (or there never was one in germany with their shitty catalog) and stayed on private trackers until now. I suspect it won't change any time soon either with all the fragmentation going on and i absolutely refuse to deal with their stupid DRM measures.

Re: Mullvad: Diskless infrastructure using stboot in beta

#36

Post by azalemeth »

kfreds wrote: post #26
oefrha wrote: post #10

For people wondering how the hell a user can audit the server is diskless or whatever, the goal appears to be using TPM to provide remote attestation for all code in the boot path. See https://www.system-transparency.org/ .

Correct! Thank you for highlighting that. Here are some additional details for those interested. We intend to make use of TPM for remote attestation of the current boot chain, reproducible builds to provide a strong link from source code to build artifacts, and a transparency log for a historical record of previously used boot chains, artifacts, WireGuard server keys, and related signatures. As dtx1 mentioned elsewhe…

This all sounds very exciting. Where will you draw the line between public and private – at the moment your consumer-facing app is on github, but less "server side" stuff (in common with many other VPN providers). I understand that probably you want to keep the database of "active numbers" private, but if I understand you correctly, you want to move to a model where anyone can download your in-memory image, run it in a VM, and audit it independently. I would welcome this. I'm particularly interested in how you maintain access to your bare-metal machines (e.g. do you have ssh / a serial console enabled)

Re: Mullvad: Diskless infrastructure using stboot in beta

#38

Post by jack_pp »

dtx1 wrote: post #35
jack_pp wrote: post #28

Earlier quoted context omitted.

Do you actually pirate music or did you give it as a general example? I feel no need to pirate music today with all the music streaming services especially since I can find all the music I want on all the streaming services which is a world of difference compared to the video streaming services

I stopped pirating music a while ago when spotify became better than what the trackers i was on delivered. That being said, i have recently started looking into it again since spotify is dragging their asses on high quality streaming and their app support on linux started to annoy me. The alternative streaming services barely support linux at all so they aren't really an alternative for me. But you are right it's mos…

Have you tried youtube music (via youtube premium)? I'm not sure about the high quality audio part because I only listen via bluetooth. The recommendations, general app UX and the fact that I can listen via website on desktop have made me cancel spotify.

Re: Mullvad: Diskless infrastructure using stboot in beta

#40

Post by _joel »

iamjbn wrote: post #22
yamrzou wrote: post #16

A bit tangential to the main post, but I'd to share a recent positive experience with Mullvad: I am a regular user of Mullvad and recently wanted to try a different VPN, that only provides Wireguard configs (i.e. no native app). I used the default setup. For some reason, my internet connection was flaky, and when it disconnected and reconnected, my traffic leaked. That never happened to me with Mullvad as the app com…

Agree, Mullvad provides really good VPN service. I faced almost zero downtimes / speed throttles. It establishes quick connection with server (maybe because it uses wireguard). Anyway, I'm a regular user and I think paying 5E worth it.

Seconded. Very occasionally I'll have to swap servers in a location but that's super infrequent and it's not exactly a primary tier location that I'm using. One of those things I can generally just setup and leave working.
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