Question

In my app, user can upload files to a ftp server. To open the connection and write to the server, I need to use username and password. Having FTP username and password in the code looks like a security issue.

Can someone please tell me how can I securely store this in my code and use it to connect to the server?

Thanks a lot!

Answer 1

If this is FTP, then you are sending the credentials over the network unencrypted. If you expect to protect these credentials, you’ve already lost, because anyone with any interest can easily sniff the password off of the wireless network. I have a simple rig set up all the time for just this kind of network sniffing from iPhone.

If FTP is your only option, then you should acknowledge that these credentials are public, and either make the connection anonymous, or strongly limit what the credentials you provide can do.

In particular, you should ensure that the credentials (or the anonymous account) can only write and not read. If you have an FTP server that has well-known credentials that can both read and write, then it will quickly become a host for copies of software and porn.

If you can use another protocol (HTTPS, SFTP, etc.) then that’s good, but it won’t actually save you. If you send your login credentials out with the software, and they have any value, they will be reverse engineered. So while I recommend using HTTPS for uploading files, you still can’t rely on the security of credentials you send out in your program. You still have to make sure your web server is tolerant of attackers sending it random things.