SSH Key Authentication Fails with macOS Ventura

When I try to authenticate with an RSA SSH key from Windows into macOS Ventura, I get a Permission denied (publickey). error. However, If I run the same code against macOS Monterrey, it works correctly. I’m attaching a repro solution so you can give it a try.

Repro Steps:

• Pre-requisites:

  • Copy the content of the testKey.pub file (included in the test project) into /Users/.<userName>/ssh/authorized_keys in the Mac

• Assign the corresponding values to the host and userName variables in the Program.cs file of the attached project

• Build and run the console app

Expected Results: the console should connect to the host with the given username and included private key (testKey)

Current Results: the console doesn’t connect and show a Permission denied (publickey). error instead

Notes:

• The attached SSH key pair has been generated using this command: ssh-keygen -b 2048 -t rsa -m PEM -f "<filePath/>" -q -N "<passPhrase/>"

• If I try to SSH connect to macOS Ventura with a Windows command prompt using the same key, it works correctly

SshNetVenturaRepro.zip

[phu-mai-jemmic]

This solution works for me 0. (Backup ~/.ssh/ folder)

1. If your ssh config and private/public keys are in /etc/ssh/ before upgrading the MacOS

• copy ssh_config to ~/.ssh/config
• copy all private/public keys to ~/.ssh/

1. Adding the following lines at the end of ~/.ssh/config

HostkeyAlgorithms +ssh-rsa
PubkeyAcceptedAlgorithms +ssh-rsa
KexAlgorithms +diffie-hellman-group1-sha1

[Pratap22]

As the solution mentioned by @phu-mai-jemmic and @giccifelipe works for rsa keys, but do you know how to fix it for ecdsa keys?