In the provided Wireshark capture, we see multiple TCP SYN packets being sent from different source IP addresses to the same destination IP address(192.168.1.159:80)within a short time window. These SYN packets do not show a corresponding SYN-ACK or ACK response, indicating that these TCP connection requests are not being completed.

This pattern is indicative of aSYN flood attack, a type of Denial of Service (DoS) attack. In this attack, a malicious actor floods the target system with a high volume of TCP SYN requests, leaving the target's TCP connection queue (backlog) filled with half-open connections. This can exhaust system resources, causing legitimate connection requests to be denied or delayed.

Thecountermeasurefor this scenario, as highlighted in theCyberOps Technologies (CBRFIR) 300-215 study guideunderNetwork-Based Attacks and TCP SYN Flood Attacks, involves:

Increasing the backlog queue: This allows the server to hold more half-open connections.

Recycling the oldest half-open connections: This ensures that legitimate connections have a chance to be established if the backlog fills up.