Mysniff is a libpcap sniffer with RC4 encryption. It sniffs the first 128 bytes of data sent to ftp / telnet / pop2 / pop3 / imap & rlogin servers, therefore revealing the logins & passwords used.
You can download it from the following link: https://packetstormsecurity.com/files/download/26260/mysniff-1.0.tar.gz
Source: https://packetstormsecurity.com/files/26260/mysniff-1.0.tar.gz.html