The victim responded with a SYN-ACK to confirm the connection, but since there was no response, it sends it again and again, using up all it’s resources! Also, since the attacker used a fake address, the administrator will have a much more difficult time tracing the source of the attack. We can see that the attacker sent many SYN packets (with spoofed addresses) to the victim. When we send a SYN packet, we’re requesting to establish a connection. If you haven’t already read the second recon article, I suggest you do so in order to understand the TCP three-way handshake. Well, it’s all about the TCP three-way handshake.

But you may be asking “ What does SYN have to do with using up resources?“.

SYN FloodingĪs we previously stated, a SYN flood is sending an insane amount of requests to a server in order to use up all it’s resources. We’re not only going to be launching a SYN flood, but we’re going to spoof our address so we don’t get thrown in the big house! Before we launch the attack, let’s deeper discuss the concept of SYN flooding. All the administrator has to do is look at the logs and turn our address into the authorities, then we’re behind bars in a matter of days. The problem with DoS attacks is that when we send all these packets the server, it has our address in it. When these requests are processed, it will take up the server’s resources, and will render it unable to respond to any actual users trying to use it. This sends requests to a server as fast as it can. There are mutliple kinds of DoS attacks, but today we’re going to launching a SYN flood.

This allows us to do many things with it including recon, possibly some basic exploitation, but for now we’re going to use it to launch a DoS attack. There is a tool by the name of hping3 that allows the attacker to craft and send custom packets. This is done by expensing all resources, so that they cannot be used by others. Not to be confused with DDoS, a DoS attack is when a single host attempts to overwhelm a server or another host. Welcome back everyone, lets talk about DoS attacks and hping3! DoS attacks are some of, if not the, most common attack (DoS stands for Denial of Service).

Hping6