"Survives a browser restart: no" seems to imply any method which tried to use QUIC alone would be highly unreliable.
Privacy implications of the QUIC protocol [pdf]
11–20 of 21 posts
Re: Privacy implications of the QUIC protocol [pdf]
#12This is about Google's QUIC ("gQUIC") and is based on a version from 2018. It explains in the Related Work section at the end that the IETF QUIC protocol has different properties. The trade discussed between keeping information for longer to make everything faster versus throwing it away frequently to avert tracking is _everywhere_ already. It's in your HTTP/1.1 web browser's Cookie behaviour, it's in the TLS impleme…
Putting the keys over DNS seems really clever. With DoH are requests bundled in a single session or is the session stood up and torn down per? I assume it's the former or this proposal wouldn't have gotten far but I've never actually bothered to check that far into DoH.
Re: Privacy implications of the QUIC protocol [pdf]
#13This is about Google's QUIC ("gQUIC") and is based on a version from 2018. It explains in the Related Work section at the end that the IETF QUIC protocol has different properties. The trade discussed between keeping information for longer to make everything faster versus throwing it away frequently to avert tracking is _everywhere_ already. It's in your HTTP/1.1 web browser's Cookie behaviour, it's in the TLS impleme…
Putting the keys over DNS seems really clever. With DoH are requests bundled in a single session or is the session stood up and torn down per? I assume it's the former or this proposal wouldn't have gotten far but I've never actually bothered to check that far into DoH.
Proposals of putting keys in DNS has a long history in IETF protocol development, it was always (?) shot down.
It was also the basis of deploying ubiquitous end2end IPsec on the internet, attempted by FreeSwan.
Re: Privacy implications of the QUIC protocol [pdf]
#14This is about Google's QUIC ("gQUIC") and is based on a version from 2018. It explains in the Related Work section at the end that the IETF QUIC protocol has different properties. The trade discussed between keeping information for longer to make everything faster versus throwing it away frequently to avert tracking is _everywhere_ already. It's in your HTTP/1.1 web browser's Cookie behaviour, it's in the TLS impleme…
Putting the keys over DNS seems really clever. With DoH are requests bundled in a single session or is the session stood up and torn down per? I assume it's the former or this proposal wouldn't have gotten far but I've never actually bothered to check that far into DoH.
A DNS query wrapped as HTTP actually makes a canonically good example of a safe TLS 1.3 0-RTT transaction so in principle you don't need to keep sessions alive.
In your first (1-RTT) DNS lookup you agree a PSK (a secret key) with the DNS via DoH server.
On the next DNS via DoH lookup you send only one message, it goes like this:
Hi, it's me again. (The rest of the message is encrypted using the PSK). Here's a freshness check. I want to ask AAAA? www.google.com and also let's agree a new key for the next time I do this. Thanks, bye.
The DoH server will probably reply like this:
Hi. (The entire rest of the message is encrypted using the PSK). Here's proof I'm still me passing your freshness check. AAAA www.google.com answer is some:ipv6:address and yes, here is a new PSK for next time.
This is the same number of messages back and forth as with traditional UDP DNS albeit the messages are a little bit bigger now, and so it incurs the same latency.
Because this is 0-RTT the DoH server can't always be sure if it has seen your query before (doing this is trivial in a toy system with e.g. one DoH server on a Linux box but hard at scale with a distributed system). So a bad guy could replay the query. But, it's just a DNS query so replaying it doesn't achieve anything useful, and this doesn't help the bad guy learn anything about the query, they don't get to find out what it said or what the answer means.
[ Edited to remove mis-remembered DH for resumption, alas TLS 1.3 resumption PSKs are not forward secret ]
Re: Privacy implications of the QUIC protocol [pdf]
#15Regarding QUIC and tracking, has anyone heard about MASQUE protocol proposal?
https://tools.ietf.org/id/draft-schinazi-masque-01.html
any thought on this?
Re: Privacy implications of the QUIC protocol [pdf]
#16This is about Google's QUIC ("gQUIC") and is based on a version from 2018. It explains in the Related Work section at the end that the IETF QUIC protocol has different properties. The trade discussed between keeping information for longer to make everything faster versus throwing it away frequently to avert tracking is _everywhere_ already. It's in your HTTP/1.1 web browser's Cookie behaviour, it's in the TLS impleme…
They also state that IETF QUIC proposals don’t seem to cover all aspects like abuse of the source-address token.
To my understanding, the more various identifiers you can muster, the more effective you are at identity stitching across data sets, resulting higher fidelity profiles. Are we at that point already where we’re ok at just waving off at another way to track what we do online?
Meanwhile, it seems theres already an implementation out there that covers ~7% of web traffic and is subject to this behavior. It’s been implemented single handedly by a company thats saying standards are moving too slow for it, far too often these days. That company also conveniently has a lot of stakes in the tracking game.
Re: Privacy implications of the QUIC protocol [pdf]
#17The network layer can already be used for tracking in multiple ways, including HTTPS sessions, ETags, and cached files with identifiers. When browsers partition the network layer they need to partition connection state as well, which includes QUIC/HTTP3 state. Safari already does this, and it looks to me like Chrome and Firefox are doing it too: https://www.jefftk.com/p/shared-cache-is-going-away (Disclosure: I work…
Yes, theres other ways to be tracked at the network level, sure. I don't see how that changes the discourse?
Beyond the straight technical implications, isn't it concerning that a single company can roll out its own protocol across the server and browser stacks, implicating 7% of web traffic? Would it be more concerning if the same company has certain interest in improving its tracking and data collection capabilities?
Also, I was expecting to find details around browsers implementing some form of network level partitioning at that link you posted, but failed. Care to spell it out for me?
Re: Privacy implications of the QUIC protocol [pdf]
#18Regarding QUIC and tracking, has anyone heard about MASQUE protocol proposal? https://tools.ietf.org/id/draft-schinazi-masque-01.html any thought on this?
It's nice in that it enables higher performance than previous "looks like a standard web server" due to QUIC but other than that there isn't too much to say. It's just a straw man proposal so the implementation details aren't there to talk about and it's not a new idea outside of binding to QUIC as the primary transport.
Re: Privacy implications of the QUIC protocol [pdf]
#19"The source-address token is a unique, authenticated-encrypted data block provided by the server, which cannot be decrypted by the client. For the purpose of IP address spoofing prevention, it contains the users publicly visible IP address and a timestamp as seen by the server." Compare ... http://curvecp.org/security.html "Does CurveCP provide client address authentication? No. IP addresses are not secure in any mea…
So, I think you've completely misunderstood what's going on here. What QUIC is doing here is to prevent _spoofing_, whereas what DJB is talking about is the futility of using IP addresses as _identity_ Why does this matter? QUIC servers often have lots of bandwidth available to them and offer 0-RTT, so they can be used for an amplified denial-of-service attack. Bad Guys send packets "from" your IP address to the QUIC…
The paper discusses how source address token might be used in tracking and thus online advertising services, Google's business.
The online tracking and advertising industry and companies selling to that industry such as Google believe IP addresses, when combined with other information, tell something valuable about consumers.
Perhaps users of the "modern web browsers" cannot or will not manually control generation or storage of source address tokens. Hence the need for papers like this one, pleading with the organisations controlling the browsers to change the software. That software is of course written by employees of companies and parents of companies that are paid directly or indirectly from sales of internet advertising services.
Probably the folks creating these protocols never thought about the implications of the design on internet advertising services. However, from the perspective of people selling internet advertising services, the association/non-association of IP addresses with public keys seems like it might be significant, regardless of its intended purpose to the protocol designers. People buying those online ad services are likely to understand the potential value of IP address information, e.g., they might think it tells them something about geo-location. If so, they might also see the added value in the combination of IP address with a unique identifier.
Re: Privacy implications of the QUIC protocol [pdf]
#20The network layer can already be used for tracking in multiple ways, including HTTPS sessions, ETags, and cached files with identifiers. When browsers partition the network layer they need to partition connection state as well, which includes QUIC/HTTP3 state. Safari already does this, and it looks to me like Chrome and Firefox are doing it too: https://www.jefftk.com/p/shared-cache-is-going-away (Disclosure: I work…
The issue of using the browser cache to perform timing attacks, which you mentioned in the post above, has been known for two decades: https://sip.cs.princeton.edu/pub/webtiming.pdf
The fix you mentioned (getting rid of shared caching) is discussed in the above article from 2000.
Genuinely surprised this hasn't been fixed earlier.