OpenSSH 7.4 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:
http://www.openssh.com/donations.html
Future deprecation notice
=========================
We plan on retiring more legacy cryptography in future releases,
specifically:
* In approximately August 2017, removing remaining support for the
SSH v.1 protocol (client-only and currently compile-time disabled).
* In the same release, removing support for Blowfish and RC4 ciphers
and the RIPE-MD160 HMAC. (These are currently run-time disabled).
* Refusing all RSA keys smaller than 1024 bits (the current minimum
is 768 bits)
* The next release of OpenSSH will remove support for running sshd(8)
with privilege separation disabled.
* The next release of portable OpenSSH will remove support for
OpenSSL version prior to 1.0.1.
This list reflects our current intentions, but please check the final
release notes for future releases.
Potentially-incompatible changes
================================
This release includes a number of changes that may affect existing
configurations:
* This release removes server support for the SSH v.1 protocol.
* ssh(1): Remove 3des-cbc from the client's default proposal. 64-bit
block ciphers are not safe in 2016 and we don't want to wait until
attacks like SWEET32 are extended to SSH. As 3des-cbc was the
only mandatory cipher in the SSH RFCs, this may cause problems
connecting to older devices using the default configuration,
but it's highly likely that such devices already need explicit
configuration for key exchange and hostkey algorithms already
anyway.
* sshd(8): Remove support for pre-authentication compression.
Doing compression early in the protocol probably seemed reasonable
in the 1990s, but today it's clearly a bad idea in terms of both
cryptography (cf. multiple compression oracle attacks in TLS) and
attack surface. Pre-auth compression support has been disabled by
default for >10 years. Support remains in the client.
* ssh-agent will refuse to load PKCS#11 modules outside a whitelist
of trusted paths by default. The path whitelist may be specified
at run-time.
* sshd(8): When a forced-command appears in both a certificate and
an authorized keys/principals command= restriction, sshd will now
refuse to accept the certificate unless they are identical.
The previous (documented) behaviour of having the certificate
forced-command override the other could be a bit confusing and
error-prone.
* sshd(8): Remove the UseLogin configuration directive and support
for having /bin/login manage login sessions.
The 1.0.2 branch of OpenSSL is the current long term support branch.
Differences between 1.0.1 and 1.0.2:
o Suite B support for TLS 1.2 and DTLS 1.2
o Support for DTLS 1.2
o TLS automatic EC curve selection.
o API to set TLS supported signature algorithms and curves
o SSL_CONF configuration API.
o TLS Brainpool support.
o ALPN support.
o CMS support for RSA-PSS, RSA-OAEP, ECDH and X9.42 DH.
Security fixes from the previous version (1.0.1t) in NetBSD:
o OCSP Status Request extension unbounded memory growth (CVE-2016-6304)
o SWEET32 Mitigation (CVE-2016-2183)
o OOB write in MDC2_Update() (CVE-2016-6303)
o Malformed SHA512 ticket DoS (CVE-2016-6302)
o OOB write in BN_bn2dec() (CVE-2016-2182)
o OOB read in TS_OBJ_print_bio() (CVE-2016-2180)
o Pointer arithmetic undefined behaviour (CVE-2016-2177)
o Constant time flag not preserved in DSA signing (CVE-2016-2178)
o DTLS buffered message DoS (CVE-2016-2179)
o DTLS replay protection DoS (CVE-2016-2181)
o Certificate message OOB reads (CVE-2016-6306)
The 1.0.2 branch of OpenSSL is the current long term support branch.
Differences between 1.0.1 and 1.0.2:
o Suite B support for TLS 1.2 and DTLS 1.2
o Support for DTLS 1.2
o TLS automatic EC curve selection.
o API to set TLS supported signature algorithms and curves
o SSL_CONF configuration API.
o TLS Brainpool support.
o ALPN support.
o CMS support for RSA-PSS, RSA-OAEP, ECDH and X9.42 DH.
Security fixes from the previous version (1.0.1t) in NetBSD:
o OCSP Status Request extension unbounded memory growth (CVE-2016-6304)
o SWEET32 Mitigation (CVE-2016-2183)
o OOB write in MDC2_Update() (CVE-2016-6303)
o Malformed SHA512 ticket DoS (CVE-2016-6302)
o OOB write in BN_bn2dec() (CVE-2016-2182)
o OOB read in TS_OBJ_print_bio() (CVE-2016-2180)
o Pointer arithmetic undefined behaviour (CVE-2016-2177)
o Constant time flag not preserved in DSA signing (CVE-2016-2178)
o DTLS buffered message DoS (CVE-2016-2179)
o DTLS replay protection DoS (CVE-2016-2181)
o Certificate message OOB reads (CVE-2016-6306)
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:
http://www.openssh.com/donations.html
Future deprecation notice
=========================
We plan on retiring more legacy cryptography in a near-future
release, specifically:
* Refusing all RSA keys smaller than 1024 bits (the current minimum
is 768 bits)
* Removing server-side support for the SSH v.1 protocol (currently
compile-time disabled).
* In approximately 1 year, removing all support for the SSH v.1
protocol (currently compile-time disabled).
This list reflects our current intentions, but please check the final
release notes for future releases.
Changes since OpenSSH 7.2
=========================
This is primarily a bugfix release.
Security
--------
* sshd(8): Mitigate a potential denial-of-service attack against
the system's crypt(3) function via sshd(8). An attacker could
send very long passwords that would cause excessive CPU use in
crypt(3). sshd(8) now refuses to accept password authentication
requests of length greater than 1024 characters. Independently
reported by Tomas Kuthan (Oracle), Andres Rojas and Javier Nieto.
* sshd(8): Mitigate timing differences in password authentication
that could be used to discern valid from invalid account names
when long passwords were sent and particular password hashing
algorithms are in use on the server. CVE-2016-6210, reported by
EddieEzra.Harari at verint.com
* ssh(1), sshd(8): Fix observable timing weakness in the CBC padding
oracle countermeasures. Reported by Jean Paul Degabriele, Kenny
Paterson, Torben Hansen and Martin Albrecht. Note that CBC ciphers
are disabled by default and only included for legacy compatibility.
* ssh(1), sshd(8): Improve operation ordering of MAC verification for
Encrypt-then-MAC (EtM) mode transport MAC algorithms to verify the
MAC before decrypting any ciphertext. This removes the possibility
of timing differences leaking facts about the plaintext, though no
such leakage has been observed. Reported by Jean Paul Degabriele,
Kenny Paterson, Torben Hansen and Martin Albrecht.
* sshd(8): (portable only) Ignore PAM environment vars when
UseLogin=yes. If PAM is configured to read user-specified
environment variables and UseLogin=yes in sshd_config, then a
hostile local user may attack /bin/login via LD_PRELOAD or
similar environment variables set via PAM. CVE-2015-8325,
found by Shayan Sadigh.
New Features
------------
* ssh(1): Add a ProxyJump option and corresponding -J command-line
flag to allow simplified indirection through a one or more SSH
bastions or "jump hosts".
* ssh(1): Add an IdentityAgent option to allow specifying specific
agent sockets instead of accepting one from the environment.
* ssh(1): Allow ExitOnForwardFailure and ClearAllForwardings to be
optionally overridden when using ssh -W. bz#2577
* ssh(1), sshd(8): Implement support for the IUTF8 terminal mode as
per draft-sgtatham-secsh-iutf8-00.
* ssh(1), sshd(8): Add support for additional fixed Diffie-Hellman
2K, 4K and 8K groups from draft-ietf-curdle-ssh-kex-sha2-03.
* ssh-keygen(1), ssh(1), sshd(8): support SHA256 and SHA512 RSA
signatures in certificates;
* ssh(1): Add an Include directive for ssh_config(5) files.
* ssh(1): Permit UTF-8 characters in pre-authentication banners sent
from the server. bz#2058
Bugfixes
--------
* ssh(1), sshd(8): Reduce the syslog level of some relatively common
protocol events from LOG_CRIT. bz#2585
* sshd(8): Refuse AuthenticationMethods="" in configurations and
accept AuthenticationMethods=any for the default behaviour of not
requiring multiple authentication. bz#2398
* sshd(8): Remove obsolete and misleading "POSSIBLE BREAK-IN
ATTEMPT!" message when forward and reverse DNS don't match. bz#2585
* ssh(1): Close ControlPersist background process stderr except
in debug mode or when logging to syslog. bz#1988
* misc: Make PROTOCOL description for direct-streamlocal@openssh.com
channel open messages match deployed code. bz#2529
* ssh(1): Deduplicate LocalForward and RemoteForward entries to fix
failures when both ExitOnForwardFailure and hostname
canonicalisation are enabled. bz#2562
* sshd(8): Remove fallback from moduli to obsolete "primes" file
that was deprecated in 2001. bz#2559.
* sshd_config(5): Correct description of UseDNS: it affects ssh
hostname processing for authorized_keys, not known_hosts; bz#2554
* ssh(1): Fix authentication using lone certificate keys in an agent
without corresponding private keys on the filesystem. bz#2550
* sshd(8): Send ClientAliveInterval pings when a time-based
RekeyLimit is set; previously keepalive packets were not being
sent. bz#2252
Portability
-----------
* ssh(1), sshd(8): Fix compilation by automatically disabling ciphers
not supported by OpenSSL. bz#2466
* misc: Fix compilation failures on some versions of AIX's compiler
related to the definition of the VA_COPY macro. bz#2589
* sshd(8): Whitelist more architectures to enable the seccomp-bpf
sandbox. bz#2590
* ssh-agent(1), sftp-server(8): Disable process tracing on Solaris
using setpflags(__PROC_PROTECT, ...). bz#2584
* sshd(8): On Solaris, don't call Solaris setproject() with
UsePAM=yes it's PAM's responsibility. bz#2425
Checksums:
==========
- SHA1 (openssh-7.3.tar.gz) = b1641e5265d9ec68a9a19decc3a7edd1203cbd33
- SHA256 (openssh-7.3.tar.gz) = vS0X35qrX9OOPBkyDMYhOje/DBwHBVEV7nv5rkzw4vM=
- SHA1 (openssh-7.3p1.tar.gz) = bfade84283fcba885e2084343ab19a08c7d123a5
- SHA256 (openssh-7.3p1.tar.gz) = P/uYmm3KppWUw7VQ1IVaWi4XGMzd5/XjY4e0JCIPvsw=
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
===============
- Please read http://www.openssh.com/report.html
Security bugs should be reported directly to openssh@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.
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:
http://www.openssh.com/donations.html
Future deprecation notice
=========================
We plan on retiring more legacy cryptography in a near-future
release, specifically:
* Refusing all RSA keys smaller than 1024 bits (the current minimum
is 768 bits)
* Removing server-side support for the SSH v.1 protocol (currently
compile-time disabled).
* In approximately 1 year, removing all support for the SSH v.1
protocol (currently compile-time disabled).
This list reflects our current intentions, but please check the final
release notes for future releases.
Changes since OpenSSH 7.2
=========================
This is primarily a bugfix release.
Security
--------
* sshd(8): Mitigate a potential denial-of-service attack against
the system's crypt(3) function via sshd(8). An attacker could
send very long passwords that would cause excessive CPU use in
crypt(3). sshd(8) now refuses to accept password authentication
requests of length greater than 1024 characters. Independently
reported by Tomas Kuthan (Oracle), Andres Rojas and Javier Nieto.
* sshd(8): Mitigate timing differences in password authentication
that could be used to discern valid from invalid account names
when long passwords were sent and particular password hashing
algorithms are in use on the server. CVE-2016-6210, reported by
EddieEzra.Harari at verint.com
* ssh(1), sshd(8): Fix observable timing weakness in the CBC padding
oracle countermeasures. Reported by Jean Paul Degabriele, Kenny
Paterson, Torben Hansen and Martin Albrecht. Note that CBC ciphers
are disabled by default and only included for legacy compatibility.
* ssh(1), sshd(8): Improve operation ordering of MAC verification for
Encrypt-then-MAC (EtM) mode transport MAC algorithms to verify the
MAC before decrypting any ciphertext. This removes the possibility
of timing differences leaking facts about the plaintext, though no
such leakage has been observed. Reported by Jean Paul Degabriele,
Kenny Paterson, Torben Hansen and Martin Albrecht.
* sshd(8): (portable only) Ignore PAM environment vars when
UseLogin=yes. If PAM is configured to read user-specified
environment variables and UseLogin=yes in sshd_config, then a
hostile local user may attack /bin/login via LD_PRELOAD or
similar environment variables set via PAM. CVE-2015-8325,
found by Shayan Sadigh.
New Features
------------
* ssh(1): Add a ProxyJump option and corresponding -J command-line
flag to allow simplified indirection through a one or more SSH
bastions or "jump hosts".
* ssh(1): Add an IdentityAgent option to allow specifying specific
agent sockets instead of accepting one from the environment.
* ssh(1): Allow ExitOnForwardFailure and ClearAllForwardings to be
optionally overridden when using ssh -W. bz#2577
* ssh(1), sshd(8): Implement support for the IUTF8 terminal mode as
per draft-sgtatham-secsh-iutf8-00.
* ssh(1), sshd(8): Add support for additional fixed Diffie-Hellman
2K, 4K and 8K groups from draft-ietf-curdle-ssh-kex-sha2-03.
* ssh-keygen(1), ssh(1), sshd(8): support SHA256 and SHA512 RSA
signatures in certificates;
* ssh(1): Add an Include directive for ssh_config(5) files.
* ssh(1): Permit UTF-8 characters in pre-authentication banners sent
from the server. bz#2058
Bugfixes
--------
* ssh(1), sshd(8): Reduce the syslog level of some relatively common
protocol events from LOG_CRIT. bz#2585
* sshd(8): Refuse AuthenticationMethods="" in configurations and
accept AuthenticationMethods=any for the default behaviour of not
requiring multiple authentication. bz#2398
* sshd(8): Remove obsolete and misleading "POSSIBLE BREAK-IN
ATTEMPT!" message when forward and reverse DNS don't match. bz#2585
* ssh(1): Close ControlPersist background process stderr except
in debug mode or when logging to syslog. bz#1988
* misc: Make PROTOCOL description for direct-streamlocal@openssh.com
channel open messages match deployed code. bz#2529
* ssh(1): Deduplicate LocalForward and RemoteForward entries to fix
failures when both ExitOnForwardFailure and hostname
canonicalisation are enabled. bz#2562
* sshd(8): Remove fallback from moduli to obsolete "primes" file
that was deprecated in 2001. bz#2559.
* sshd_config(5): Correct description of UseDNS: it affects ssh
hostname processing for authorized_keys, not known_hosts; bz#2554
* ssh(1): Fix authentication using lone certificate keys in an agent
without corresponding private keys on the filesystem. bz#2550
* sshd(8): Send ClientAliveInterval pings when a time-based
RekeyLimit is set; previously keepalive packets were not being
sent. bz#2252
Portability
-----------
* ssh(1), sshd(8): Fix compilation by automatically disabling ciphers
not supported by OpenSSL. bz#2466
* misc: Fix compilation failures on some versions of AIX's compiler
related to the definition of the VA_COPY macro. bz#2589
* sshd(8): Whitelist more architectures to enable the seccomp-bpf
sandbox. bz#2590
* ssh-agent(1), sftp-server(8): Disable process tracing on Solaris
using setpflags(__PROC_PROTECT, ...). bz#2584
* sshd(8): On Solaris, don't call Solaris setproject() with
UsePAM=yes it's PAM's responsibility. bz#2425
Checksums:
==========
- SHA1 (openssh-7.3.tar.gz) = b1641e5265d9ec68a9a19decc3a7edd1203cbd33
- SHA256 (openssh-7.3.tar.gz) = vS0X35qrX9OOPBkyDMYhOje/DBwHBVEV7nv5rkzw4vM=
- SHA1 (openssh-7.3p1.tar.gz) = bfade84283fcba885e2084343ab19a08c7d123a5
- SHA256 (openssh-7.3p1.tar.gz) = P/uYmm3KppWUw7VQ1IVaWi4XGMzd5/XjY4e0JCIPvsw=
Please note that the SHA256 signatures are base64 encoded and not
hexadecimal (which is the default for most checksum tools). The PGP
key used to sign the releases is available as RELEASE_KEY.asc from
the mirror sites.
Reporting Bugs:
===============
- Please read http://www.openssh.com/report.html
Security bugs should be reported directly to openssh@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.
+ Bring over change from pkgsrc to add version.asc signature verification
to complement the noversion.asc cleartext signatures
+ Update version to 20160616
to avoid some unknown miscompilation in endian_convert() that causes
ssh to exit on some output (for me, "cc -v".)
note in HACKS. we should investigate this further if possible as
this seems to indicate a strict aliasing violation. there certainly
are 32 and 64 bit object arrays being accessed with 8 bit accessors,
but i don't have time currently.
*) Prevent padding oracle in AES-NI CBC MAC check
A MITM attacker can use a padding oracle attack to decrypt traffic
when the connection uses an AES CBC cipher and the server support
AES-NI.
This issue was introduced as part of the fix for Lucky 13 padding
attack (CVE-2013-0169). The padding check was rewritten to be in
constant time by making sure that always the same bytes are read and
compared against either the MAC or padding bytes. But it no longer
checked that there was enough data to have both the MAC and padding
bytes.
This issue was reported by Juraj Somorovsky using TLS-Attacker.
(CVE-2016-2107)
[Kurt Roeckx]
*) Fix EVP_EncodeUpdate overflow
An overflow can occur in the EVP_EncodeUpdate() function which is used for
Base64 encoding of binary data. If an attacker is able to supply very large
amounts of input data then a length check can overflow resulting in a heap
corruption.
Internally to OpenSSL the EVP_EncodeUpdate() function is primarly used by
the PEM_write_bio* family of functions. These are mainly used within the
OpenSSL command line applications, so any application which processes data
from an untrusted source and outputs it as a PEM file should be considered
vulnerable to this issue. User applications that call these APIs directly
with large amounts of untrusted data may also be vulnerable.
This issue was reported by Guido Vranken.
(CVE-2016-2105)
[Matt Caswell]
*) Fix EVP_EncryptUpdate overflow
An overflow can occur in the EVP_EncryptUpdate() function. If an attacker
is able to supply very large amounts of input data after a previous call to
EVP_EncryptUpdate() with a partial block then a length check can overflow
resulting in a heap corruption. Following an analysis of all OpenSSL
internal usage of the EVP_EncryptUpdate() function all usage is one of two
forms. The first form is where the EVP_EncryptUpdate() call is known to be
the first called function after an EVP_EncryptInit(), and therefore that
specific call must be safe. The second form is where the length passed to
EVP_EncryptUpdate() can be seen from the code to be some small value and
therefore there is no possibility of an overflow. Since all instances are
one of these two forms, it is believed that there can be no overflows in
internal code due to this problem. It should be noted that
EVP_DecryptUpdate() can call EVP_EncryptUpdate() in certain code paths.
Also EVP_CipherUpdate() is a synonym for EVP_EncryptUpdate(). All instances
of these calls have also been analysed too and it is believed there are no
instances in internal usage where an overflow could occur.
This issue was reported by Guido Vranken.
(CVE-2016-2106)
[Matt Caswell]
*) Prevent ASN.1 BIO excessive memory allocation
When ASN.1 data is read from a BIO using functions such as d2i_CMS_bio()
a short invalid encoding can casuse allocation of large amounts of memory
potentially consuming excessive resources or exhausting memory.
Any application parsing untrusted data through d2i BIO functions is
affected. The memory based functions such as d2i_X509() are *not* affected.
Since the memory based functions are used by the TLS library, TLS
applications are not affected.
This issue was reported by Brian Carpenter.
(CVE-2016-2109)
[Stephen Henson]
*) EBCDIC overread
ASN1 Strings that are over 1024 bytes can cause an overread in applications
using the X509_NAME_oneline() function on EBCDIC systems. This could result
in arbitrary stack data being returned in the buffer.
This issue was reported by Guido Vranken.
(CVE-2016-2176)
[Matt Caswell]
*) Modify behavior of ALPN to invoke callback after SNI/servername
callback, such that updates to the SSL_CTX affect ALPN.
[Todd Short]
*) Remove LOW from the DEFAULT cipher list. This removes singles DES from the
default.
[Kurt Roeckx]
*) Only remove the SSLv2 methods with the no-ssl2-method option. When the
methods are enabled and ssl2 is disabled the methods return NULL.
[Kurt Roeckx]
and UseLogin=yes in sshd_config, then a hostile local user may
attack /bin/login via LD_PRELOAD or similar environment variables
set via PAM.
CVE-2015-8325, found by Shayan Sadigh, via Colin Watson
https://anongit.mindrot.org/openssh.git/commit/?\
id=85bdcd7c92fe7ff133bbc4e10a65c91810f88755
XXX: pullup-7
christos