Which of the following is a computer program that is designed to assess computers, computer systems, networks, or applications for weaknesses?

A.
Vulnerability scanner

B.
Paros

C.
Port scanner

D.
SYN scan

Explanation:
Vulnerability scanners work on the concept of port scanners. In addition to identifying hosts and open ports, a vulnerability scanner also provides information on the associated vulnerabilities. Vulnerability scanners are very useful to identify out-of-date software versions, applicable patches, system upgrades, etc. The weakness of these scanners is that they can only identify surface vulnerabilities. These scanners are unable to address the overall risk level of a scanned network.

Answer option B is incorrect. Paros is a Web application vulnerability scanner that supports editing /viewing HTTP/HTTPS messages on-the-fly to change items such as cookies and form fields. It also includes various features, such as Web traffic recorder, Web spider, hash calculator, and a scanner for testing common Web application attacks such as SQL injection and cross-site scripting. A SYN scan is a type of TCP scanning. This scan type is also known as ‘half-open scanning’ because it does not open a full TCP connection. The port scanner generates a SYN packet. If the target port is open, it responds with a SYN-ACK packet. The scanner host responds with an RST packet that causes the connector before the handshake is completed.

Answer option C is incorrect. A port scanner is a software tool that is designed to search a network host for open ports. This tool is often used by administrators to check the security of their networks. It is also used by hackers to compromise the network and systems.