medium
6.8
CWE
310
Advisory Published
CVE Published
Updated

CVE-2013-4073

First published: Fri Jun 28 2013(Updated: )

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: <a href="http://www.ruby-lang.org/en/news/2013/06/27/hostname-check-bypassing-vulnerability-in-openssl-client-cve-2013-4073/">http://www.ruby-lang.org/en/news/2013/06/27/hostname-check-bypassing-vulnerability-in-openssl-client-cve-2013-4073/</a>

Credit: cve@mitre.org

Affected SoftwareAffected VersionHow to fix
redhat/ruby<2.0.0
2.0.0
redhat/ruby<1.9.3
1.9.3
redhat/ruby<1.8.7
1.8.7
Ruby=1.8.6-26
Ruby=1.8.7
Ruby=1.8.7-p160
Ruby=1.8.7-p17
Ruby=1.8.7-p173
Ruby=1.8.7-p174
Ruby=1.8.7-p22
Ruby=1.8.7-p248
Ruby=1.8.7-p249
Ruby=1.8.7-p299
Ruby=1.8.7-p301
Ruby=1.8.7-p302
Ruby=1.8.7-p330
Ruby=1.8.7-p334
Ruby=1.8.7-p352
Ruby=1.8.7-p357
Ruby=1.8.7-p358
Ruby=1.8.7-p370
Ruby=1.8.7-p371
Ruby=1.8.7-p373
Ruby=1.8.7-p71
Ruby=1.8.7-p72
Ruby=1.8.7-preview1
Ruby=1.8.7-preview2
Ruby=1.8.7-preview3
Ruby=1.8.7-preview4
Ruby=1.9.3
Ruby=1.9.3-p0
Ruby=1.9.3-p125
Ruby=1.9.3-p194
Ruby=1.9.3-p286
Ruby=1.9.3-p383
Ruby=1.9.3-p385
Ruby=1.9.3-p392
Ruby=1.9.3-p426
Ruby=1.9.3-p429
Ruby=2.0.0-p0
Ruby=2.0.0-p195
Ruby=2.0.0-preview1
Ruby=2.0.0-preview2
Ruby=2.0.0-rc1
Ruby=2.0.0-rc2

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2013-4073?

    The severity of CVE-2013-4073 is classified as medium risk due to improper handling of null bytes in hostnames.

  • How do I fix CVE-2013-4073?

    To fix CVE-2013-4073, upgrade your Ruby version to 2.0.0, 1.9.3, or 1.8.7.

  • Which versions of Ruby are affected by CVE-2013-4073?

    CVE-2013-4073 affects Ruby versions 1.8.6 through 2.0.0, including 1.8.7 and 1.9.3.

  • What is the impact of CVE-2013-4073?

    The impact of CVE-2013-4073 is that it allows an attacker to bypass hostname verification in SSL connections.

  • Is there a patch for CVE-2013-4073?

    No specific patch is provided; users must upgrade to the recommended Ruby versions to mitigate CVE-2013-4073.

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