[openssh-unix-announce] Announce: OpenSSH 7.0 released

Damien Miller djm at cvs.openbsd.org
Tue Aug 11 22:53:23 AEST 2015

OpenSSH 7.0 has just been released. It will be available from the
mirrors listed at http://www.openssh.com/ shortly.

OpenSSH is a 100% complete SSH protocol 2.0 implementation and
includes sftp client and server support. OpenSSH also includes
transitional support for the legacy SSH 1.3 and 1.5 protocols
that may be enabled at compile-time.

Once again, we would like to thank the OpenSSH community for their
continued support of the project, especially those who contributed
code or patches, reported bugs, tested snapshots or donated to the
project. More information on donations may be found at:

Future deprecation notice

We plan on retiring more legacy cryptography in the next release

 * Refusing all RSA keys smaller than 1024 bits (the current minimum
   is 768 bits)

 * Several ciphers will be disabled by default: blowfish-cbc,
   cast128-cbc, all arcfour variants and the rijndael-cbc aliases
   for AES.

 * MD5-based HMAC algorithms will be disabled by default.

This list reflects our current intentions, but please check the final
release notes for OpenSSH 7.1 when it is released.

Changes since OpenSSH 6.9

This focus of this release is primarily to deprecate weak, legacy
and/or unsafe cryptography.


 * sshd(8): OpenSSH 6.8 and 6.9 incorrectly set TTYs to be world-
   writable. Local attackers may be able to write arbitrary messages
   to logged-in users, including terminal escape sequences.
   Reported by Nikolay Edigaryev.

 * sshd(8): Portable OpenSSH only: Fixed a privilege separation
   weakness related to PAM support. Attackers who could successfully
   compromise the pre-authentication process for remote code
   execution and who had valid credentials on the host could
   impersonate other users.  Reported by Moritz Jodeit.

 * sshd(8): Portable OpenSSH only: Fixed a use-after-free bug
   related to PAM support that was reachable by attackers who could
   compromise the pre-authentication process for remote code
   execution. Also reported by Moritz Jodeit.

 * sshd(8): fix circumvention of MaxAuthTries using keyboard-
   interactive authentication. By specifying a long, repeating
   keyboard-interactive "devices" string, an attacker could request
   the same authentication method be tried thousands of times in
   a single pass. The LoginGraceTime timeout in sshd(8) and any
   authentication failure delays implemented by the authentication
   mechanism itself were still applied. Found by Kingcope.

Potentially-incompatible Changes

 * Support for the legacy SSH version 1 protocol is disabled by
   default at compile time.

 * Support for the 1024-bit diffie-hellman-group1-sha1 key exchange
   is disabled by default at run-time. It may be re-enabled using
   the instructions at http://www.openssh.com/legacy.html

 * Support for ssh-dss, ssh-dss-cert-* host and user keys is disabled
   by default at run-time. These may be re-enabled using the
   instructions at http://www.openssh.com/legacy.html

 * Support for the legacy v00 cert format has been removed.

 * The default for the sshd_config(5) PermitRootLogin option has
   changed from "yes" to "prohibit-password".

 * PermitRootLogin=without-password/prohibit-password now bans all
   interactive authentication methods, allowing only public-key,
   hostbased and GSSAPI authentication (previously it permitted
   keyboard-interactive and password-less authentication if those
   were enabled).

New Features

 * ssh_config(5): add PubkeyAcceptedKeyTypes option to control which
   public key types are available for user authentication.

 * sshd_config(5): add HostKeyAlgorithms option to control which
   public key types are offered for host authentications.

 * ssh(1), sshd(8): extend Ciphers, MACs, KexAlgorithms,
   HostKeyAlgorithms, PubkeyAcceptedKeyTypes and HostbasedKeyTypes
   options to allow appending to the default set of algorithms
   instead of replacing it. Options may now be prefixed with a '+'
   to append to the default, e.g. "HostKeyAlgorithms=+ssh-dss".

 * sshd_config(5): PermitRootLogin now accepts an argument of
   'prohibit-password' as a less-ambiguous synonym of 'without-


 * ssh(1), sshd(8): add compatability workarounds for Cisco and more
   PuTTY versions. bz#2424

 * Fix some omissions and errors in the PROTOCOL and PROTOCOL.mux
   documentation relating to Unix domain socket forwarding;
   bz#2421 bz#2422

 * ssh(1): Improve the ssh(1) manual page to include a better
   description of Unix domain socket forwarding; bz#2423

 * ssh(1), ssh-agent(1): skip uninitialised PKCS#11 slots, fixing
   failures to load keys when they are present. bz#2427

 * ssh(1), ssh-agent(1): do not ignore PKCS#11 hosted keys that wth
   empty CKA_ID; bz#2429

 * sshd(8): clarify documentation for UseDNS option; bz#2045

Portable OpenSSH

 * Check realpath(3) behaviour matches what sftp-server requires and
   use a replacement if necessary.


 - SHA1 (openssh-7.0.tar.gz) = a19ff0bad2a67348b1d01a38a9580236120b7099
 - SHA256 (openssh-7.0.tar.gz) = 4F6HV/ZqT465f3sMB2vIkXO+wrYtL5hnqzAymfbZ1Jk=

 - SHA1 (openssh-7.0p1.tar.gz) = d8337c9eab91d360d104f6dd805f8b32089c063c
 - SHA256 (openssh-7.0p1.tar.gz) = /VkySToZ9MgRU9gS7k4EK0m707dZqz2TRKvswrwUheU=

Please note that the PGP key used to sign releases was recently rotated.
The new key has been signed by the old key to provide continuity. It is
available from the mirror sites as RELEASE_KEY.asc.

Reporting Bugs:

- Please read http://www.openssh.com/report.html
  Security bugs should be reported directly to openssh at openssh.com

OpenSSH is brought to you by Markus Friedl, Niels Provos, Theo de Raadt,
Kevin Steves, Damien Miller, Darren Tucker, Jason McIntyre, Tim Rice and
Ben Lindstrom.

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