Nathalie would like to perform a reliable scan against a remote target. She is not concerned about being stealth at this point. Which of the following type of scans would be the most accurate and reliable?
A.
A TCP Connect scan
B.
A FIN scan
C.
A UDP scan
D.
A half-scan
Explanation:
A TCP Connect scan, named after the Unix connect( ) system call is the most accurate scanning method. If a port is open the operating system completes the TCP three-way handshake, and the port scanner immediately closes the connection. Otherwise an error code is returned.
Example of a three-way handshake followed by a reset:
Source Destination Summary
————————————————————————————- [192.168.0.8 ] [ 192.168.0.10] TCP: D=80 S=49389 SYN SEQ=3362197786 LEN=0 WIN=5840 [192.168.0.10] [192.168.0.8] TCP: D=49389 S=80 SYN ACK=3362197787 SEQ=58695210 LEN=0 WIN=65535
[192.168.0.8 ] [ 192.168.0.10] TCP: D=80 S=49389 ACK=58695211 WIN<<2=5840 [192.168.0.8 ] [ 192.168.0.10] TCP: D=80 S=49389 RST ACK=58695211 WIN<<2=5840