Why FTP exposes more than the file
In traditional FTP, the client and server exchange control messages to arrange a transfer. Among them are commands that identify the user and provide the password. Because ordinary FTP does not encrypt this conversation, those credentials travel in a form that can be read by someone able to monitor the network path—not merely guessed from the file being transferred.
FTP also typically uses a separate connection for the file data. That separation can make the process feel like two different things: one channel handles instructions and sign-in, while another carries the file. But the split does not protect the password. Without encryption, an observer may capture the login exchange and reuse the credentials to access the account, potentially long after the original transfer has ended.
The fix must protect the connection
A password change alone does not solve the underlying problem: the next login would still be exposed if it used unencrypted FTP. The safer choice is a transfer method that encrypts the connection, such as FTPS, which adds TLS encryption to FTP, or SFTP, a separate file-transfer protocol that runs over SSH. They are not interchangeable names for the same protocol, so the client and server must support the same option.
The practical consequence is that a routine file upload can disclose access to more than one file. If the same password is reused elsewhere, the captured login may put those other accounts at risk too. Protecting the transfer therefore means shielding the credentials as well as the data.
