Issue #9424 has been updated by B Kelly.


 Martin.Bosslet / gmail.com wrote:
 >
 > Rolling your own defaults is dangerous: Even skilled developers like the
 > Debian developers can get it wrong sometimes, with disastrous consequences.
 
 The Debian blunder has been referenced twice in this discussion, but I think
 the comparison is not apt.
 
 The Debian maintainer _removed lines of code_ from the OpenSSL PRNG
 implementation. [1]
 
 This is hardly in the same category as tightening the defaults to exclude
 specific ciphers or protocol features already known to be weak or exploitable.
 
 
 > It hurts even more that in such cases everyone will start pointing fingers,
 > asking: "Why didn't you stick to the library defaults???"
 
 As opposed to asking: "Why didn't you remove known weak ciphers and exploitable
 protocol features from the defaults when you were warned about them???"
 
 
 > I would prefer a whitelisting approach instead of blacklisting as in the
 > patch that was proposed. Blacklisting is never airtight, as it doesn't protect
 > us from future shitty algorithms creeping in.
 
 I wonder.  In the blacklisting case, we're not required to make guesses about
 the future.  We're merely switching off already-known weak or exploitable
 features.
 
 Whitelisting goes a step further, gambling that what we know today about the
 subset of defaults considered superior will continue to hold true down the road.
 
 It's not clear to me that's better than the more conservative step of simply
 blacklisting specific defaults already known to be problematic.
 
 
 
 Regards,
 
 Bill
 
 
 [1] The details are perhaps interesting: http://research.swtch.com/openssl

----------------------------------------
Bug #9424: ruby 1.9 & 2.x has insecure SSL/TLS client defaults 
https://bugs.ruby-lang.org/issues/9424#change-44540

* 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
----------------------------------------
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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