312-50v11 Attack Practice Questions

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 the third is a binary file is named "nc." The FTP server's access logs show that the anonymous user account logged in to the server, uploaded the files, and 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, 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?

• AA. File system permissions
• BB. Privilege escalation
• CC. Directory traversal
• DD. Brute force login

When a normal TCP connection starts, a destination host receives a SYN (synchronize/start) packet from a source host and sends back a SYN/ACK (synchronize acknowledge). The destination host must then hear an ACK (acknowledge) of the SYN/ACK before the connection is established. This is referred to as the "TCP three-way handshake." While waiting for the ACK to the SYN ACK, a connection queue of finite size on the destination host keeps track of connections waiting to be completed. This queue typically empties quickly since the ACK is expected to arrive a few milliseconds after the SYN ACK. How would an attacker exploit this design by launching TCP SYN attack?

• AA. Attacker generates TCP SYN packets with random destination addresses towards a victim host
• BB. Attacker floods TCP SYN packets with random source addresses towards a victim host
• CC. Attacker generates TCP ACK packets with random source addresses towards a victim host
• DD. Attacker generates TCP RST packets with random source addresses towards a victim host