SFTP connection through Java asking for weird authentication

Question

So I\'m writing a little program that needs to connect to a remote server through SFTP, pull down a file, and then processes the file. I came across JSch through some answer

Answer 1

While the solution in the self-accepted answer is correct, it lacks any explanation.

The problem is that the OP have a Kerberos/GSSAPI authentication set as the preferred (the JSch default). Yet OP does not seem to actually use/want it, as OP claims not to specify any username or password for the Kerberos prompts.

The solution is to remove the Kerberos/GSSAPI (gssapi-with-mic) from the list of preferred authentication methods:

session.setConfig(
    "PreferredAuthentications", 
    "publickey,keyboard-interactive,password");

Answer 2

All answers are correct, I'll just add here the way it can be done for Spring Integration when trying to integrate with an SFTP server.

So, if you are using SFTP Spring Integration and the weird user and password for Kerberos is prompting in the same way the OP is asking.

Then modify your Spring configuration (I'm using Java Spring Integration config, if you are using XML config you can try to translate it yourself - I really don't like XML config :P ):

So in the bean you are using as SessionFactory you need to add this change in config:

@Bean
public SessionFactory<LsEntry> sftpSessionFactory() {
    DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory(true);
    factory.setHost("hostname");
    factory.setPort(22);
    factory.setUser("username");
    factory.setPassword("superstrongpassword");
    factory.setAllowUnknownKeys(true);
    factory.setSessionConfig(buildSessionProperties());
    return new CachingSessionFactory<>(factory);
}

/**
 * Build JSch property PreferredAuthentications without "gssapi-with-mic"
 * This way it won't prompt for Kerberos authentication every time it tries to connect
 * to the SFTP.
 */
private Properties buildSessionProperties() {
    Properties sessionProperties = new Properties();
    sessionProperties.setProperty("PreferredAuthentications", "publickey,keyboard-interactive,password");
    return sessionProperties;
}

Answer 3

Thought I'd post an answer here since in case anyone else ends up running into a similar issue. Turns out I am missing a piece of code that makes all the difference. I just needed to add

session.setConfig("PreferredAuthentications", 
                  "publickey,keyboard-interactive,password");

before

session.connect();

and everything works perfectly now.