Thousands of businesses are targeted by cyber attacks each year. While some of these cyber attacks involve the deployment of malware, others involve spam traffic. SYN flood is a type of spam-based cyber attack. It can consume server resources while subsequently creating performance issues. What is a SYN flood attack exactly?

SYN Flood Attacks Explained

A SYN flood attack is a type of denial-of-service (DoS) cyber attack that involves the use of rapid connection requests. If your business has a server that’s connected to a public network, such as the internet, a hacker may send an excessive number of connection requests to it. Servers can only process so many connection requests at any given time. SYN attacks exploit this weakness by “flooding” them with an excessive number of connection requests.

How SYN Flood Attacks Work

During a SYN flood attack, a hacker will send connection requests to a server. These connection requests come in the form of SYN packets. SYN packets are an essential part of the Transmission Control Protocol (TCP), which governs the communication between hosts and clients on a network.

Upon receiving a SYN packet, the server will respond with its own packet. The server will send a SYN-ACK packet back to the client who sent the SYN packet. In normal communications, the client will send an ACK packet to the server, resulting in a connection to the server. But SYN flood attacks take a different approach.

There are no ACK packets during a SYN flood attack. The client is the hacker. And after receiving a SYN-ACK packet from the server, the hacker behind the SYN flood attack won’t send the necessary ACK packet. Therefore, the hacker won’t establish a connection with the server. Instead, the hacker will continue to send these connection requests while attempting to flood the server.

Tips to Protect Against SYN Flood Attacks

You can protect against SYN flood attacks by using a firewall. Installing a firewall on your business’s server will allow you to filter malicious traffic. Once properly configured, the firewall will block malicious traffic from attempting to connect to your business’s server.

Another tip to protect against SYN flood attacks is to increase the maximum backlog of your business’s server. The maximum backlog is the maximum number of connection requests it can process at any given time. The higher the maximum backlog, the more connection requests your business’s server can handle.