FTPPasswordSniffer 6.0 could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. We recommend checking the downloaded files with any free antivirus.
This free software is an intellectual property of SecurityXploded. The following versions: 4.5 and 4.0 are the most frequently downloaded ones by the program users. FTPPasswordSniffer is included in Internet & Network Tools. The program's installer file is commonly found as FTPPasswordSniffer.exe.
From the developer:
FTP Password Sniffer is a universal FTP password recovery tool for any of your favorite FTP application such as FileZilla or SmartFtp. It can not only recover the lost FTP account password but can sniff and catch any of the FTP account passwords passing through your network. Thus, it is a useful tool for penetration testers.
You may want to check out more software, such as FTP Password Decryptor, which might be related to FTPPasswordSniffer.