openjdk team mailing list archive

[Nathan Bryant <nrb@xxxxxxxxxxxxx>]

Public bug reported:

Due to [CBCATT], some server administrators (including the webservices
gateway for a major airline reservations provider) choose to disable CBC
ciphersuites unless the protocol level is TLSv1.1 or later; [TLS1.1]
introduced an explicit CBC IV to guard against such attacks. (See
[TLS1.1] section 1.1) On such servers, disabling all CBC ciphersuites
may leave only RC4 as a trusted cipher.

JDK7 introduced support for TLSv1.2, but chose not to enable it by
default, due to a policy of not changing such defaults in minor
revisions. JDK8 enables TLSv1.2 by default.

On Ubuntu, due to USN-2696-1, starting with the openjdk-7-jre-7u79-2.5.6-0ubuntu1.12.04.1 package, RC4 is disabled by default but the protocol default remains TLSv1.0. This can leave no remaining trusted ciphers, and
negotiation can fail.

Workaround: on OpenJDK7, it is possible to either use
SSLContext.getInstance("TLSv1.2") or re-enable RC4 via
SSLSocket.setEnabledCipherSuites(), but neither workaround is viable if
one doesn't have access to 3rd-party source code.

References:

   [TLS1.1]   Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.1", RFC 4346, April 2006.
              https://www.ietf.org/rfc/rfc4346.txt

   [CBCATT]   Moeller, B., "Security of CBC Ciphersuites in SSL/TLS:
              Problems and Countermeasures",
              http://www.openssl.org/~bodo/tls-cbc.txt.

** Affects: openjdk-7 (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1482924

Title:
  Regressions due to USN-2696-1

Status in openjdk-7 package in Ubuntu:
  New

Bug description:
  Due to [CBCATT], some server administrators (including the webservices
  gateway for a major airline reservations provider) choose to disable
  CBC ciphersuites unless the protocol level is TLSv1.1 or later;
  [TLS1.1] introduced an explicit CBC IV to guard against such attacks.
  (See [TLS1.1] section 1.1) On such servers, disabling all CBC
  ciphersuites may leave only RC4 as a trusted cipher.

  JDK7 introduced support for TLSv1.2, but chose not to enable it by
  default, due to a policy of not changing such defaults in minor
  revisions. JDK8 enables TLSv1.2 by default.

  On Ubuntu, due to USN-2696-1, starting with the openjdk-7-jre-7u79-2.5.6-0ubuntu1.12.04.1 package, RC4 is disabled by default but the protocol default remains TLSv1.0. This can leave no remaining trusted ciphers, and
  negotiation can fail.

  Workaround: on OpenJDK7, it is possible to either use
  SSLContext.getInstance("TLSv1.2") or re-enable RC4 via
  SSLSocket.setEnabledCipherSuites(), but neither workaround is viable
  if one doesn't have access to 3rd-party source code.

  References:

     [TLS1.1]   Dierks, T. and E. Rescorla, "The Transport Layer Security
                (TLS) Protocol Version 1.1", RFC 4346, April 2006.
                https://www.ietf.org/rfc/rfc4346.txt

     [CBCATT]   Moeller, B., "Security of CBC Ciphersuites in SSL/TLS:
                Problems and Countermeasures",
                http://www.openssl.org/~bodo/tls-cbc.txt.

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