Issue #9424 has been updated by Martin Bosslet.


Yusuke Endoh wrote:
> Cooperatively with some committers, I investigated the current condition of default settings in OpenSSL (and OS X).  It is very complicated.  Correct me if I'm wrong.

Thanks for that!

> * [IMPORTANT] Emboss's patch does NOT always work.  There is no way Ruby can fix the issue if OpenSSL 0.9.8 built with zlib is used.

> If I'm correct, when we release the patch, it should be emphasized that the patch is NOT perfect, e.g., it will not help those who are using the old OpenSSL 0.9.8 provided by MacPorts.  Eventually, each user must choose a secure OS/distribution carefully, and update it appropriately.

That's the kind of proliferation I was talking about. Although Ruby OpenSSL is a direct consumer of OpenSSL, we already face a more complicated task of trying to fix the problem on our end. a) I want to apologize for overlooking this, but then b) I want to emphasize again that this is exactly what I was talking about earlier. I would be OK with patching the defaults, but only in line with what @mame and @shyouhei already said: it must be clear to everyone that this patch will not relieve you from keeping OpenSSL up to date. This should never be our goal, and I hope it's not what anyone is asking from us, because I believe it's simply impossible. It would mean trying to merge every security bugfix ever made in all versions of OpenSSL at least since 0.9.6 in a way that yields one single patch that fits all versions that might be used with Ruby OpenSSL. That's insane! If someone is willingly running OpenSSL 0.9.8 or even earlier, it should not become our burden to fix this.

Like @shyouhei, I still believe the best solution would be asking OpenSSL to fix this for all of us. But if the majority is for patching, OK. I'll update the patch with a real whitelist, appending it for review here.

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Bug #9424: ruby 1.9 & 2.x has insecure SSL/TLS client defaults 
https://bugs.ruby-lang.org/issues/9424#change-44615

* Author: Jeff Hodges
* Status: Assigned
* Priority: Normal
* Assignee: Martin Bosslet
* Category: ext/openssl
* Target version: current: 2.2.0
* ruby -v: ruby 2.1.0p0 (2013-12-25 revision 44422) [x86_64-darwin12]
* Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN, 2.1: UNKNOWN
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Ruby 1.9, 2.0, and 2.1 use insecure defaults for SSL/TLS client connections. They have inherited or overridden configs that make the OpenSSL-controlled connections insecure. Note: both OpenSSL's and Ruby's defaults in all tested versions are currently insecure. Confirmation of the issues with Ruby's TLS client can be done with the code in [1].

Ruby is using TLS compression by default. This opens Ruby clients to the CRIME attack[2].

Ruby also uses a variety of insecure cipher suites. These cipher suites either use key sizes much smaller than the currently recommended size, making brute forcing a decryption easy, or do not check the veracity of the server's certificate making them susceptible to man-in-the-middle attacks[3][4].

Ruby also appears to allow SSLv2 connections by default. It does so by first trying to connect with a SSLv2 client hello with a higher SSL/TLS version inside of it which allows SSLv2 servers to work. SSLv2 was broken in the 1990s and is considered unsafe.

These issues expose Ruby users to attacks that have been known for many years, and are trivial to discover. These defaults are often build specific, and are not the same across platforms, but are consistently poor (the code in [1] can evaluate the build). A patch from a core developer on the security@ list is attached. However, the patch does not correct the suspect SSLv2 configuration. It is believed that Ruby 1.8 is also a concern, but, since it was obsoleted, it's not been investigated.

A report similar to this was sent to security / ruby-lang.org four days ago. The Ruby core developers have been unable to patch these problems in a timely manner for it for what I and others believe are concerning reasons. This ticket is being made to allow engineers outside of the small group that are on security@ to protect themselves from these attacks.

[1] https://gist.github.com/cscotta/8302049
[2] https://www.howsmyssl.com/s/about.html#tls-compression
[3] https://www.howsmyssl.com/s/about.html#insecure-cipher-suites
[4] TLS_DHE_DSS_WITH_DES_CBC_SHA - small keys
TLS_DHE_RSA_WITH_DES_CBC_SHA - small keys
TLS_ECDH_anon_WITH_3DES_EDE_CBC_SHA - MITM
TLS_ECDH_anon_WITH_AES_128_CBC_SHA - MITM
TLS_ECDH_anon_WITH_AES_256_CBC_SHA - MITM
TLS_ECDH_anon_WITH_RC4_128_SHA - MITM
TLS_RSA_WITH_DES_CBC_SHA - small keys
TLS_SRP_SHA_WITH_3DES_EDE_CBC_SHA - MITM
TLS_SRP_SHA_WITH_AES_128_CBC_SHA - MITM
TLS_SRP_SHA_WITH_AES_256_CBC_SHA - MITM

---Files--------------------------------
ruby_ssl.patch (1.08 KB)
change_ssl_defaults.diff (1.24 KB)


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