A network administrator discovers several unknown files in the root directory of his Linux FTP server. One of the files is a tarball, two are shell script files, and last one is a binary- file is named "nc_ ". The FTP server's access logs show that the anonymous user account logged into the server, uploaded the files, extracted the contents of the tarball and ran the script using a function provided by the FTP server's software. The
ps command shows that the
nc_* file is running as process nc, and the
netstat command shows the nc process is listening on a network port.
What kind of vulnerability must be present to make this remote attack possible?
Directory traversal, Privilege escalation, Brute force login or File system permissions
Which is the correct answer ?