Problem Statement

Apache provides lot of libraries for common utility functions for Java. One such common library is FTP library which provides better functionality to do FTP and FTPS calls. The reference to apache ftp library is: Apache Ftp

The problem comes while using FTPS. When developer uses login method of this library while authentication, it prints username and password in console, which is a huge security concern. Also, it exposes user credentials to logs. And, anyone can read those credentials if he or she has access to those logs.

Example

FTPClient ftpClient = null;
FTPSClient ftps = new FTPSClient("TLS", false);

//accept all for now
ftps.setTrustManager(TrustManagerUtils.getAcceptAllTrustManager());

//verbose
ftps.addProtocolCommandListener(
  new PrintCommandListener( new PrintWriter(new OutputStreamWriter(System.out, "UTF-8"), true)));

ftpClient = ftps;
//set connect timeout

ftpClient.setConnectTimeout(config.getConnectTimeout());
ftpClient.connect(host);
ftps.execPROT("P");
//SSL mode

if(ftpClient.login(username, password)) {
  //successfully login
}
else {
  //error condition
}

Example output:

220-Isilon OneFS v7.2.1.1
220
AUTH TLS
234 Proceed with negotiation.
PROT P
200 PROT now Private.
USER USERNAME
331 Please specify the password.
PASS PASSWORD

The Solution

For best security practices, we should not put passwords anywhere in logs. Lets come to the solution for this problem. We need to modify the code a little bit for this mess. See below code:

 FTPClient ftpClient = null;
 FTPSClient ftps = new FTPSClient("TLS", false);

 //accept all for now
 ftps.setTrustManager(TrustManagerUtils.getAcceptAllTrustManager());

 //verbose
 ftps.addProtocolCommandListener(new ProtocolCommandListener() {
  @Override public void protocolReplyReceived(ProtocolCommandEvent arg0) { }
  @Override public void protocolCommandSent(ProtocolCommandEvent arg0) { }
 });

 ftpClient = ftps;

 //set connect timeout
 ftpClient.setConnectTimeout(config.getConnectTimeout());

 ftpClient.connect(host);

 ftps.execPROT("P");
 //SSL mode
 if(ftpClient.login(username, password)) {
   //successfully login
 }
 else {
   //error condition
 }

Result

Now, you will not see previous mess in console, or in logs.

Note: Above code is just to show the problem of showing passwords in concole. I will write a complete better implementation of ftp and ftps apis.