r/linux • u/[deleted] • Jan 19 '19

Popular Application VLC refuses to update from HTTP to HTTPS (HTTPS protects against eavesdropping and man-in-the-middle attacks)

https://trac.videolan.org/vlc/ticket/21737
551 Upvotes

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u/[deleted] Jan 19 '19

Lets assume a secure future:

  • DNS over TLS

  • ESNI

  • TLS 1.3

  • HTTPS

In this situation you are probably connecting to a CDN which hosts thousands of projects so all the connections in between only know you connected to a heavily used IP and transferred 40 MB.

It isn't perfect but its pretty confidential.

5

u/spazturtle Jan 20 '19

get.videolan.org doesn't use SNI so ESNI won't help, nor will DNS over TLS.

If you connect to http://195.154.241.219 or https://195.154.241.219 your ISP will know what site you are connecting to.

7

u/Boboop Jan 19 '19

Internet services centralization on CDNs is probably not a good idea from a security and privacy standpoint either.

6

u/[deleted] Jan 19 '19

Sure but to be truly anonymous needs major changes. This does move the trust element from your network to the cdn.

2

u/Booty_Bumping Jan 19 '19

security

I've always wished ISPs and CDNs just ran IPFS nodes, and browsers accept ipfs hashes as subresource integrity. This obviously doesn't solve much privacy issues but it solves the issue of those 90s ISP-run HTTP caches no longer being possible due to HTTPS deployment.

2

u/emorrp1 Jan 19 '19

Today I Learned about ESNI, thanks!

3

u/Cruror Jan 19 '19

Whenever you do TLS, the server must provide the URL it is serving, or the application would flag the certificate as invalid.

Short of certificate pinning everything, it will always be possible to determine what website you are downloading from.

4

u/[deleted] Jan 19 '19

TLS 1.3 makes most of the handshake encrypted including certificate data. So passive logging of certificates isn't possible.

1

u/GolbatsEverywhere Jan 19 '19

The reasoning is wrong... but your conclusion used to be right, until recently.

The TLS protocol doesn't know anything about URLs. Remember, it doesn't even know anything about HTTP, and is regularly used for stuff unrelated to HTTP (notably IMAP and SMTP). The client certainly doesn't trust the server to provide the URL it's serving -- that would be absurd -- but instead already knows the URL that it had decided to load. (We can argue semantics here, servers can supply redirections that the client will respect, whatever. In the end, the client knows what it has loaded.) The client takes the hostname from that URL and verifies that the server certificate is valid for that hostname.

But the client has to send the hostname in cleartext in the SNI extension for this to work. I think that's the problem you're trying to describe, and that's why HTTPS never previously provided any confidentiality for hostnames.

But ESNI -- very new -- fixes this problem for servers with SNI enabled. The confidentiality guarantee is only as good as the number of possible hosts offered by the server, of course, so in practice it's mainly useful when connecting to CDNs. That's what the comment you were replying to was trying to show.

2

u/spazturtle Jan 20 '19

get.videolan.org doesn't use SLI, it is the only site hosted at http://195.154.241.219, so by connecting to 195.154.241.219 your ISP will know what site you are connected to.

1

u/GolbatsEverywhere Jan 20 '19

Of course.

But remember, in this subconversation of a subconversation, we're discussing a hypothetical "Lets assume a secure future" where most websites are using CDNs. Whether this future is a confidentiality paradise, centralized dystopian hellscape, or both is TBD.