Answer:
Chris Evans, author of vsftpd announced that the master site for vsftpd was compromised and that the latest version of vsftpd (vsftpd-2.3.4.tar.gz) was backdoored. The backdoor payload is interesting. In response to a smiley face in the FTP username, a TCP callback shell is attempted. There is no obfuscation.
Step-by-step explanation: