Eccouncil Exam 312-38 Topic 9 Question 109 Discussion

In Wireshark, to detect TCP Null Scan attempts, the filter used istcp.flags==0. This filter will show packets where no TCP flags are set, which is indicative of a TCP Null Scan. A TCP Null Scan is a type of network reconnaissance technique where the attacker sends TCP packets with no flags set to the target system. If the target system responds with a RST packet, it indicates that the port is closed, while no response suggests that the port is open or filtered. This method is used because some systems do not log these null packets, allowing the scan to go unnoticed.