Download OpenSSH 4.4

OpenSSH is a software suite for the SSH protocol with which higher security can be achieved. Applications such as telnet, rlogin and ftp send data unencrypted over the network, the login data can then be read in a simple way. With OpenSSH, this data is sent encrypted so that eavesdropping, connection hijacking and other network-level attacks are no longer possible. In addition, there are also various secure tunneling options and authentication methods available. The development team has released version 4.4 with the following release notes:

Security bugs resolved in this release:

• Fix a pre-authentication denial of service found by Tavis Ormandy, that would cause sshd(8) to spin until the login grace time expired.
• Fix an unsafe signal hander reported by Mark Dowd. The signal handler was vulnerable to a race condition that could be exploited to perform a pre-authentication denial of service. On portable OpenSSH, this vulnerability could theoretically lead to pre-authentication remote code execution if GSSAPI authentication is enabled, but the likelihood of successful exploitation appears remote.
• On portable OpenSSH, fix a GSSAPI authentication abort that could be used to determine the validity of usernames on some platforms.

This release includes the following new functionality and fixes:

• Implemented conditional configuration in sshd_config(5) using the “Match” directive. This allows some configuration options to be selectively overridden if specific criteria (based on user, group, hostname and/or address) are met. So far a useful subset of post-authentication options are supported and more are expected to be added in future releases.
• Add support for Diffie-Hellman group exchange key agreement with a final hash of SHA256.
• Added a “ForceCommand” directive to sshd_config(5). Similar to the command=”…” option accepted in ~/.ssh/authorized_keys, this forces the execution of the specified command regardless of what the user requested. This is very useful in conjunction with the new “Match” option.
• Add a “PermitOpen” directive to sshd_config(5). This mirrors the permitopen=”…” authorized_keys option, allowing fine-grained control over the port-forwardings that a user is allowed to establish.
• Add optional logging of transactions to sftp server(8).
• ssh(1) will now record port numbers for hosts stored in ~/.ssh/authorized_keys when a non-standard port has been requested.
• Add an “ExitOnForwardFailure” option to cause ssh(1) to exit (with a non-zero exit code) when requested port forwardings could not be established.
• Extend sshd_config(5) “SubSystem” declarations to allow the specification of command-line arguments.
• Replacement of all integer overflow susceptible invocations of malloc(3) and realloc(3) with overflow-checking equivalents.
• Many manual fixes and improvements
• New portable OpenSSH-specific features:
  • Add optional support for SELinux, controlled using the –with-selinux configure option (experimental)
  • Add optional support for Solaris process contracts, enabled using the –with-solaris-contracts configure option (experimental) This option will also include SMF metadata in Solaris packages built using the “make package” target
  • Add optional support for OpenSSL hardware accelerators (engines), enabled using the –with-ssl-engine configure option.
• Bugs from fixed:
  • #482 – readconf doesn’t accept paths with spaces in them.
  • #906 – syslog messages from sshd [net] lost.
  • #975 – Kerberos authentication timing can leak information about account validity.
  • #981 – Flow stopped in SSH2.
  • #1102 – C program ‘write’ with zero length hangs.
  • #1129 – sshd hangs for command-only invocations due to fork/child signals.
  • #1131 – error “buffer_append_space:alloc not supported”
  • #1138 – Passphrase asked for (but ignored) if key file permissions too liberal..
  • #1156 – Closes connection after Cc is pressed on QNX.
  • #1157 – ssh-keygen doesn’t handle DOS line breaks.
  • #1159 – %u and %h not handled in IdentityFile.
  • #1161 – scp -r fails.
  • #1162 – Inappropriate sequence of syslog messages.
  • #1166 – openssh-4.3p1 has some issues compiling.
  • #1171 – configure can’t always figure out LLONG_MAX..
  • #1173 – scp reports lost connection for very large files.
  • #1177 – Incorrect sshrc file location in Makefile.in.
  • #1179 – sshd incorrectly rejects connections due to IP options.
  • #1181 – configure should detect when openssl-0.9.8x needs -ldl.
  • #1186 – ssh tries multiple times to open unprotected keys.
  • #1188 – keyboard-interactive should not allow retry after pam_acct_mgmt fails.
  • #1193 – Open ssh will not allow changing of passwords on usernames greater than 8 characters..
  • #1201 – Bind address information is not specified in command line help messages.
  • #1203 – configure.ac is missing an open [.
  • #1207 – sshd does not clear unsuccessful login count on non-interactive logins.
  • #1218 – GSSAPI client code permits SPNEGO usage.
  • #1221 – Banner only suppressed at log level = QUIET (used to be at log level
• Fixes to memory and file descriptor leaks reported by the Coverity static analysis tool
• Fixes to inconsistent pointer checks reported by the Stanford SATURN tool

[break]OpenSSH is available in two flavors, one specifically for OpenBSD and one for the other operating systems:
OpenSSH 4.4 – OpenBSD
OpenSSH 4.4 – Portable (Linux, Solaris, FreeBSD, NetBSD, AIX, IRIX, HP-UX, Mac OS X)