Syncplify Server! v6.2.28 released

Importance of this update: [OPTIONAL]
What’s changed?
  • Restored support for PKI authentication (SSH2/SCP/SFTP) using insecure RSA keys (SHA1 signature, insecure moduli, …), while secure RSA keys have never been dropped. We understand that transitioning to secure keys can be a challenge for some users. While we’ve provided resources and recommendations for dropping RSA keys for PKI authentication and switching to more secure keys (ECDSA, Ed25519, …), we recognize that some users may require more time, hence the choice to re-enable PKI auth support for these insecure keys. This does not make our server software less secure, it simply means it may allow certain insecure algorithms, but security-conscious users will simply configure our server software not to use them, thus keeping it completely safe and secure

IMPORTANT NOTE: those who are running the “worker” system service under a different account (not System or LocalSystem) will need to re-configure the service to run under such account after upgrading from any version number <= 6.1.12)

Upgrading from v6.x.y is a simple and fairly automatic process: simply download the latest version from the official download page, and install it over the existing version, all of your settings and license will be kept.

If, instead, you’re upgrading from an older (v4/v5) version, you find the upgrade instructions in our knowledge base.

Thank you all for trusting our software with your secure file transfers!

Syncplify Server! v6.2.18 released

Importance of this update: NORMAL
What’s changed?
  • On new installs the setup process does not create an RSA host key anymore, upgrades and restores from backups will not remove your existing RSA keys though
  • The repairhttp command-line verb now uses better defaults for HTTPS/WebClient! configuration
  • Better HTTPS/WebClient! default values are also used now when creating a new Virtual Site
  • Fixed the list of host key algorithms returned to SSH/SFTP clients, now it won’t include algorithms for keys your server doesn’t have
  • Upgraded the compiler to the most recent version to capture several fixes and improvements in its standard library

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This is why you should use RSA host keys carefully, or just stop using them altogether

An extremely interesting research paper published in 2023 by Keegan Ryan, Kaiwen He, George A. Sullivan, and Nadia Heninger, mathematically proves yet another weakness with RSA keys – often used as host keys by/for SSH/SFTP servers – and this time it has to do with the way they are generated.

Without delving into the math itself, which is not the purpose of this blog, we would like to take this occasion to advise our customers to use stronger keys, like ECDSA or Ed25519, instead of RSA for their host keys.

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