Software Update: OpenSSH 8.8

OpenSSH encrypts network traffic to prevent eavesdropping, connection hijacking, and other network attacks. In addition, it includes the ability to set up so-called secure tunnels and supports various authentication methods. OpenSSH was developed primarily for OpenBSD; users of other operating systems can here justly. The developers released version 8.8 of OpenSSH a while ago which we still thought worth mentioning. The corresponding announcement looks like this:

OpenSSH 8.8 released

OpenSSH 8.8 has just been released. It will be available from the mirrors listed at shortly.

OpenSSH is a 100% complete SSH protocol 2.0 implementation and includes sftp client and server support.

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: donations.html

Future deprecation notice
A near-future release of OpenSSH will switch scp(1) from using the legacy scp/rcp protocol to using SFTP by default.

Legacy scp/rcp performs wildcard expansion of remote filenames (eg “scp host:* .”) through the remote shell. This has the side effect of requiring double quoting of shell meta-characters in file names included on scp(1) command-lines, otherwise they could be interpreted as shell commands on the remote side.

This creates one area of ​​potential incompatibility: scp(1) when using the SFTP protocol no longer requires this finicky and brittle quoting, and attempts to use it may cause transfers to fail. We consider the removal of the need for double-quoting shell characters in file names to be a benefit and do not intend to introduce bug- compatibility for legacy scp/rcp in scp(1) when using the SFTP protocol.

Another area of ​​potential incompatibility relates to the use of remote paths relative to other user’s home directories, for example – “scp host:~user/file /tmp”. The SFTP protocol has no native way to expand a ~user path. However, sftp-server(8) in OpenSSH 8.7 and later support a protocol extension “expand-path at openssh.com” to support this.

Security
sshd(8) from OpenSSH 6.2 through 8.7 failed to correctly initialise supplemental groups when executing an AuthorizedKeysCommand or AuthorizedPrincipalsCommand, where a AuthorizedKeysCommandUser or AuthorizedPrincipalsCommandUser directive has been set to run the command as a different user. Instead these commands would inherit the groups that sshd(8) was started with.

Depending on system configuration, inherited groups may allow AuthorizedKeysCommand/AuthorizedPrincipalsCommand helper programs to gain unintended privilege.

Neither AuthorizedKeysCommand nor AuthorizedPrincipalsCommand are enabled by default in sshd_config(5).

Potentially incompatible changes
This release disables RSA signatures using the SHA-1 hash algorithm by default. This change has been made as the SHA-1 hash algorithm is cryptographically broken, and it is possible to create chosen-prefix hash collisions for HostkeyAlgorithms +ssh-rsa
PubkeyAcceptedAlgorithms +ssh-rsa

We recommend enabling RSA/SHA1 only as a stopgap measure until legacy implementations can be upgraded or reconfigured with another key type (such as ECDSA or Ed25519).

Changes since OpenSSH 8.7
This release is motivated primarily by the above deprecation and security fix.

New features

• ssh(1): allow the ssh_config(5) CanonicalizePermittedCNAMEs directive to accept a “none” argument to specify the default behavior.

Bug fixes

• scp(1): when using the SFTP protocol, continuous transferring files after a transfer error occurs, better matching original scp/rcp behavior.
• ssh(1): fixed a number of memory leaks in multiplexing,
• ssh-keygen(1): avoid crash when using the -Y find-principals command.
• A number of documentation and manual improvements, including bz#3340, PR#139, PR#215, PR#241, PR#257

portability

• ssh-agent(1): on FreeBSD, use procctl to disable ptrace(2)
• ssh(1)/sshd(8): some fixes to the pselect(2) replacement compatibility code. bz#3345

Checksums:

• SHA1 (openssh-8.8.tar.gz) = 732947082a8998047e839cc0b4c066bf0a7e1a5b
• SHA256 (openssh-8.8.tar.gz) = AngyrPSQH255hnzU1l7y+LlVAUNcGWtuYQIFEl22nRo=
• SHA1 (openssh-8.8p1.tar.gz) = 1eb964897a4372f6fb96c7effeb509ec71c379c9
• SHA256 (openssh-8.8p1.tar.gz) = RZCJDqm7ms5Pca4zF4WjpYIyMkNRYZYO1fyGWI8zH+k=

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 from the mirror sites: https://cdn.openbsd.org/pub/OpenBSD/OpenSSH/RELEASE_KEY.asc

Please note that the OpenPGP key used to sign releases has been rotated for this release. The new key has been signed by the previous key to provide continuity.

Reporting Bugs:
Please read report.html . Security bugs should be reported directly to openssh at openssh.com