Bug 475074 – <dev-lang/ruby-{1.8.7_p374,1.9.3_p448} : hostname check bypassing vulnerability in SSL client (CVE-2013-4073)

• Status: RESOLVED FIXED
• Product: Gentoo Security

[Description Agostino Sarubbo 2013-06-28 08:16:29 UTC]

From ${URL} :

Ruby’s SSL client implements hostname identity check but it does not properly handle hostnames in 
the certificate that contain null bytes.

OpenSSL::SSL.verify_certificate_identity implements RFC2818 Server Identity check for Ruby’s SSL 
client but it does not properly handle hostnames in the subjectAltName X509 extension that contain 
null bytes.

Existing code in lib/openssl/ssl.rb uses OpenSSL::X509::Extension#value for extracting identity 
from subjectAltName. Extension#value depends OpenSSL function X509V3_EXT_print() and for dNSName of 
subjectAltName it utilizes sprintf() that is known as null byte unsafe. As the result 
Extension#value returns ‘www.ruby-lang.org’ if the subjectAltName is 
‘www.ruby-lang.org\0.example.com’ and OpenSSL::SSL.verify_certificate_identity wrongly identifies 
the certificate is for ‘www.ruby-lang.org’.

When a CA a SSL client trusts allows to issue the server certificate that has null byte in 
subjectAltName, remote attackers can obtain the certificate for ‘www.ruby-lang.org\0.example.com’ 
from the CA to spoof ‘www.ruby-lang.org’ and do man-in-the-middle between Ruby’s SSL client and SSL 
servers.


External References:

http://www.ruby-lang.org/en/news/2013/06/27/hostname-check-bypassing-vulnerability-in-openssl-client-cve-2013-4073/

This is corrected in upstream versions 2.0.0-p247, 1.9.3-p448 and 1.8.7-p374.


@maintainer(s): after the bump, in case we need to stabilize the package, please say explicitly if it is ready for the stabilization or not.

[Comment 1 Hans de Graaff 2013-06-30 08:47:49 UTC]

Fixed versions are now in the tree. The additional changes don't look very invasive, so let's continue with stabling right away:

=dev-lang/ruby-1.8.7_p374
=dev-lang/ruby-1.9.3_p448

[Comment 2 Agostino Sarubbo 2013-06-30 12:38:46 UTC]

amd64 stable

[Comment 3 Agostino Sarubbo 2013-06-30 12:43:47 UTC]

x86 stable

[Comment 4 Agostino Sarubbo 2013-06-30 13:27:37 UTC]

arm stable

[Comment 5 Agostino Sarubbo 2013-06-30 21:09:00 UTC]

ppc stable

[Comment 6 Jeroen Roovers (RETIRED) 2013-07-01 02:39:33 UTC]

Stable for HPPA.

[Comment 7 Agostino Sarubbo 2013-07-04 14:14:00 UTC]

ppc64 stable

[Comment 8 Agostino Sarubbo 2013-07-06 17:06:57 UTC]

alpha stable

[Comment 9 Agostino Sarubbo 2013-07-07 15:18:01 UTC]

ia64 stable

[Comment 10 Agostino Sarubbo 2013-07-21 17:40:11 UTC]

sh stable

[Comment 11 Agostino Sarubbo 2013-07-22 08:52:23 UTC]

sparc stable

[Comment 12 Agostino Sarubbo 2013-08-06 12:34:03 UTC]

s390 stable

[Comment 13 Chris Reffett (RETIRED) 2013-08-27 03:35:12 UTC]

GLSA vote: no.

[Comment 14 GLSAMaker/CVETool Bot 2013-08-27 03:35:26 UTC]

CVE-2013-4073 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2013-4073):
  The OpenSSL::SSL.verify_certificate_identity function in lib/openssl/ssl.rb
  in Ruby 1.8 before 1.8.7-p374, 1.9 before 1.9.3-p448, and 2.0 before
  2.0.0-p247 does not properly handle a '\0' character in a domain name in the
  Subject Alternative Name field of an X.509 certificate, which allows
  man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted
  certificate issued by a legitimate Certification Authority, a related issue
  to CVE-2009-2408.

[Comment 15 Sergey Popov 2013-09-04 06:14:18 UTC]

GLSA vote: no

Closing as noglsa