FTPNullSearch is a FTP scanner that can scan a range of IPs looking for servers that allow anonymous logins. Written for Linux.
You can download it from the following link: https://packetstormsecurity.com/files/download/65186/FTPNullSearch02.tar.gz
Source: https://packetstormsecurity.com/files/65186/FTPNullSearch02.tar.gz.html