I am writing to you as I opened an issue on eclipse-cdt/cdt GitHub repo.
ssh and sftp connection (RSE) can't connect to modern ssh server (device) because old and broken ciphers,kex, and MAC are disabled by default on the server.
As I've reported years ago on bugzilla:https://bugs.eclipse.org/bugs/show_bug.cgi?id=560571
Eclipse uses an old ssh implementation that does not support newer and safer ssh parameters.
Eclipse uses jsch library for ssh, which unfortunately seems to be discontinued.
I've found an update fork of the jsch:https://github.com/mwiede/jsch