I am using Spring Integration (Version: 6.1.2) to connect to an SFTP server. While creating an SFTPSession, I get this exception -
java.lang.IllegalStateException: failed to create SFTP Session .... Caused by: org.apache.sshd.common.SshException: Unable to negotiate key exchange for kex algorithms ( client: curve25519-sha256, [email protected], curve448-sha512, ecdh-sha2-nistp521, ecdh-sha2-nistp384, ecdh-sha2-nistp256, diffie-hellman-group-exchange-sha256, diffie-hellman-group18-sha512, diffie-hellman-group17-sha512, diffie-hellman-group16-sha512, diffie-hellman-group15-sha512, diffie-hellman-group14-sha256, ext-info-c server: diffie-hellman-group1-sha1, diffie-hellman-group14-sha1) Obviously, the server only supports the old algorithms. How do I add support for these algorithms on my SFTP session?
Here is my code -
DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory(); factory.setHost("ftp.sssss.com"); factory.setPort(Integer.valueOf(22)); factory.setAllowUnknownKeys(true); factory.setUser("user"); factory.setPassword("password"); SftpSession sftpSession = factory.getSession(); 1 Answer
Apparently those algorithms have been deprecated: .
This SO thread explains how to enable those old keys: Mina SSHD enable KEX with SHA1 in version 2.6.0.
The DefaultSftpSessionFactory supports an external SshClient:
/** * Instantiate based on the provided {@link SshClient}, e.g. some extension for HTTP/SOCKS. * @param sshClient the {@link SshClient} instance. * @param isSharedSession true if the session is to be shared. */ public DefaultSftpSessionFactory(SshClient sshClient, boolean isSharedSession) { So, you need to do like this:
SshClient client = SshClient.setUpDefaultClient(); client.setKeyExchangeFactories(NamedFactory.setUpTransformedFactories( false, BuiltinDHFactories.VALUES, ClientBuilder.DH2KEX )); client.setSignatureFactories(new ArrayList<>(BuiltinSignatures.VALUES)) and inject that client into DefaultSftpSessionFactory.
