OpenSSL in Debian Unstable drops TLS 1.0/1.1 support

https://lists.debian.org/debian-devel-announce/2017/08/msg00004.html

by jhealy • 9 years ago

147 64 9 years ago

lists.debian.org

koolba• 9 years ago

Is there a plugin or setting for Firefox or Chrome that would give me stats on server protocol support for my own interactions?

I'm pretty sure the preference is newer versions of TLS where available. So would be interesting to see if this would have any impact on ones own browsing habits (ignoring the fact that FF has its own TLS lib so wouldn't be using OpenSSL anyway).

mholt• 9 years ago

The inspector tools of both Firefox and Chrome will give you the protocol version and cipher suite selected.

sitkack• 9 years ago

I am bummed that Chrome removed it from info tip over the lock icon. One has to dive into the developer tools tab to get this info now.

simcop23872• 9 years ago

Here's an addon for firefox that'll display that for you easily. https://addons.mozilla.org/en-us/firefox/addon/cipherfox/

simcop23872• 9 years ago

On mobile since I can't edit. It doesn't show it directly by default but it's configurable. You can add $PROTOCOL to the cipher display in it's preferences for this.

rakoo• 9 years ago

I use ssleuth that gives me a bit more details and a rating: https://addons.mozilla.org/en-US/firefox/addon/ssleuth/

chickenbane• 9 years ago

Good. Debian won't be making stable any time soon, so a very reasonable timeline.

pilif7• 9 years ago

I don’t know. We have customers connect to us with their internal systems they haven’t touched in ages. I can’t possibly tell them that they need to update their infrastructure two years (Debian has a two year release cycle and has released this year) from now.

And then there are some end-users behind enterprise middle-boxes which don’t support anything beyond TLS 1.1 and I have a feeling it’s going to be difficult to communicate to them that they need to change the configuration.

This means that we'll have to package our own FTP and HTTP servers in the future. Not a big deal, but certainly not something I'm looking forward to.

Oh and our mail relay I probably have to build myself too or just disable TLS. You have no idea what shitty SSL configurations are used out there by the various systems trying to send us email.

Grumble. At this point, I might as well run Linux from scratch when most of the daemons we run won't be able to talk to a seizable chunk of the clients connecting to us any more.

In other words: if you set up Debian out of the box today, its default packages will talk to 99% of clients out there on the internet. If you set up Debian in 2019, about 30% of the clients out there won’t be able to talk to you.

And the fix won’t just be a configuration change; it will require you to manually build every single daemon you make use of.

throwaway20483• 9 years ago

I think introducing some friction here is a good idea, pre 1.2 tls/ssl are objectively broken, insecure protocols.

Unless some of these people experience some pain and fix their shit, they will never upgrade, and by extension keeping everyone that wishes to communicate with them vulnerable as well (due to BAD_GUY being able to force protocol downgrades)

Is it the right solution to accommodate them (not to mention by default out of the box which means it hurts your users without them being aware of it or able to make an informed choice) and pretend it isn't a problem, and thus putting yourself at risk too?

For the same reasons i think its highly irresponsible people like FreeBSD patch in garbage like null cipher support into ssh. It is broken let the people who have to use it for whatever weird reason deal with the burden of their broken shit, don't force it on everyone else and weaken their security.

bigbugbag2• 9 years ago

I am confused with your two years figure. With a two year release cycle in two years testing will become stable, but this change is in unstable which will become testing in two years.

Or did I miss something here ?

pdw• 9 years ago

Would it really be necessary to rebuild all daemons? It seems to me that it would be sufficient to drop in a custom libssl that doesn't disable the old protocols.

rlpb• 9 years ago

At this point, I might as well run Linux from scratch...

You might as well learn the Debian tooling and run a system with the OpenSSL package patched with a build-time change.

On Ubuntu, that'd be the same as maintaining a PPA with one source package in it. On Debian, it's effectively the same except that you'll need reprepro or a script around apt-ftparchive instead.

This is far easier than your hyperbole of running Linux from scratch.

Twirrim• 9 years ago

At a previous job they finally deprecated RC4-MD5, long after almost everyone had stopped using it.

About a week later they had to re-enable it, because it turned out a few major customers had some old SPARC (IIRC?) boxes that used the service. The extra overhead of non RC4-MD5 ciphers was crippling them. There was some seriously frantic back and forth with the customer to get the situation resolved and figure out a timeline to finally, finally, finally deprecate RC4-MD5.

yuhong• 9 years ago

How many years do you estimate.

rossy• 9 years ago

This makes me anxious, but I'm not sure if my anxiety is valid. I didn't know it was okay to disable TLS 1.0/1.1 this early. Correct me if I'm wrong, but this will affect all HTTPS web requests and web serving, as well as mail delivery and receipt from Debian sid. I'm not sure I want to only be able to surf ~90% of the encrypted web[1] and I'm not sure I'm ready to drop support for Android 4.3[2] or stock Windows 7/IE (which has TLS 1.2 switched off in Internet Options.) Not to mention all the mail servers out there running outdated crypto. I have mail in my inbox (from eg. Amazon Pay) received over TLS 1.0. As far as I understand, supporting outdated protocols like TLS 1.0 is only a problem if there is a downgrade attack that can force a server and client that speak TLS 1.2 to communicate over TLS 1.0. Otherwise, it should be fine to support TLS 1.0 to speak to older clients, while giving newer clients the option to speak over TLS 1.2.

Hopefully this announcement is correct in the assumption that support for TLS 1.2 will be high enough when Buster is released.

[1] https://www.ssllabs.com/ssl-pulse/ [2]: https://www.ssllabs.com/ssltest/clients.html

cft2• 9 years ago

Yes, you can't run a webserver on that Debian that supports tls with Android 4.3 or earlier for example.

pmlnr• 9 years ago

I'm pretty certain you're being sarcastic, but on Debian, most of the users stick to the "stock", packaged ones, instead of building their own. Indeed you can build nginx with custom ssl, but most of the Debian users won't fiddle with this.

vbernat• 9 years ago

Browsing shouldn't be affected as it doesn't use OpenSSL. However, I share your concerns. The target is the next stable (two years), but many of us are running unstable or testing.

Conan_Kudo2• 9 years ago

What are you talking about? Web servers AND web browsers both use OpenSSL. If it's disabled, you can't speak it at all in Debian.

kalleboo• 9 years ago

Does the Android 4.3 incompatibility also apply to Chrome from the Play store, or only Browser/WebViews/system APIs?

0x02• 9 years ago

Seems a little risky especially for SMTP services. Will be interesting to see how this pans out!

hannob2• 9 years ago

I predict hereby that this change won't last long.

While cryptographically it's the right move (everything below TLS 1.2 with an AEAD is cryptographically broken), this disables connectivity with half of the Internet. There is a huge number of hosts out there running on legacy hardware that won't do anything beyond TLS 1.0.

bigbugbag2• 9 years ago

And those hosts ought to up their game or disappear.

The other way to look at it is that you have security vulnerabilities because a portion of the internet is stuck in a decade old obsolete world.

r1ch• 9 years ago

It's not just about hosts. In developing countries, old generation mobile phones running Android 4.x are extremely common. Google's own metrics show 26% of Android phones are pre-5.0, and that's without the unknown number that don't have Google Services installed.

EDIT: Seems the last version of Android 4 does support TLS 1.2, but there's still a non-zero amount of users on older versions.

codemusings• 9 years ago

We're talking Debian Unstable. That change is at least 2 years out if you're running Testing on your servers or 4 years with Stable. I think that's a reasonable goal.

mmarx• 9 years ago

That change is at least 2 years out if you're running Testing on your servers or 4 years with Stable. I think that's a reasonable goal.

That's not how the Debian release process works. If everything goes well, that package may hit testing next week[0]; and it may very well be that the next stable release will be in two years.

[0] https://tracker.debian.org/pkg/openssl

mgbmtl• 9 years ago

Speaking of, disabling TLS 1.0 is a great way to reduce traffic from unwanted bots. (although I still run TLS 1.1)

If necessary, someone will create a dotdeb-equivalent for an openssl version with TLS 1.0. This is a "dammed if you do, dammed if you don't" type of thing. If they don't disable it, at the next big security issue, everyone will blame openssl/distributions for being negligent.

tombrossman• 9 years ago

Looks like this breaks fetching OpenGraph assets for some popular services, does anyone know which are not compatible? I went TLS 1.2 only a while ago for a personal site, but only tested with Twitter (which does work).

https://twitter.com/AliceWonder32/status/894468549720260608

thinkMOAR• 9 years ago

Also for MTAs? That's a bold move :)

snvzz• 9 years ago

What's appalling is how they're not switching to libressl yet.

user59944612• 9 years ago

Can we have a reminder, what is the security issue with TLS 1.0 and TLS 1.1?

hannob2• 9 years ago

The main issue is lack of authenticated encryption and in consequence padding oracles.

It turned out that fixing them thoroughly is extremely difficult. Again and again new variants of these attacks have been found and existing countermeasures have turned out to be insufficient. While these attacks are of low impact (involves timing and that's hard to pull off remotely), it's certainly not something you want in the most important crypto protocol.

TLS 1.0 has additional issues, notably the BEAST attack.

All of that can be mitigated, but it's ugly and complicated and you really just want authenticated encryption (AES-GCM or Chacha20-Poly1305), which is only available in TLS 1.2.

baby• 9 years ago

A good TLS 1.1 server implementation implementing all the fixes should be "fine". While a good TLS 1.0 client implementation should prevent the BEAST from working.

Note that all of these could run without problems if both side support the encrypt-then-MAC extension (https://tools.ietf.org/html/rfc7366).

It's a lot of "if" though, hence why we prefer TLS 1.2 which has no problems (so far). But usually when nothing do, it is still better to have something than nothing.

If you want to know more about BEAST: https://www.cryptologie.net/article/413/beast-an-explanation...

DCKing• 9 years ago

Last year I disabled TLS 1.0/1.1 on my personal server and encountered problems. Turns out Mono (Keepass2Android) and Qt (QBittorrent) libraries on Android for some reason had not enabled higher-than-TLS-1.0 support, although AFAIK they supported it at the time.

So yeah, I ended up reenabling TLS 1.0/1.1 on a system on which I had full control over the clients connecting to it. Given the difficulty and nature of current attacks, I figured the low risks to me personally weren't worth the inconvenience.

I commend the Debian project for making the push for this, but I wonder if the world is ready to be TLS 1.2+ only.

snakeanus• 9 years ago

I also have disabled all versions before TLS 1.2, any key exchange other than x25519 (I wanted to avoid the NSA curves) and all encryption/mac algorithms other than Chacha20-poly1305. It works just fine with the last Firefox ESR and Chromium that way.

OpenSSL in Debian Unstable drops TLS 1.0/1.1 support

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