Enable ssh-dss algorighthm through system variable

[abhikt48]

We need to connect many SFTP servers and some SFTP servers are still using ssh-dss algorithm for SFTP connection.

We have to use MuleSoft SFTP connector which internally uses sshd-core-2.12.1 library, by default ssh-dss algorithm are disabled because it is too weak to considered.

I'm able to communicate with these ssh-dss enabled SFTP servers using the settings below. However, I'm unable to apply the same settings in the MuleSoft SFTP connector because we can't modify their library.

sshClient.setKeyExchangeFactories(NamedFactory.setUpTransformedFactories(false,
		BuiltinDHFactories.VALUES, ClientBuilder.DH2KEX));
sshClient.setSignatureFactories(new ArrayList<>(BuiltinSignatures.VALUES));

Could someone please advise if there's a method to enable the ssh-dss algorithm via system variable settings? This would allow us to connect to ssh-dss enabled SFTP servers without any code modifications.