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Digital security is an ever-present theme in the management of any company. The greater the amount of sensitive information accumulated by the business, the more important it is to invest in protection against different types of digital attacks. And one of the main ones is the Syn Flood attack.
Knowing and preventing these attacks is one of the main obligations of IT management in companies. Without proper preparation, it can completely interrupt the company’s activities or cause the leakage of important data from customers, employees and partners.
Follow and better understand what Syn Flood is and how to protect your business against it.
What is Syn Flood?
The Syn Flood, or Flood of Syn, are a type of digital attack made with the objective of interrupting the service within a network. This happens due to a flaw in a security check that the attacker tries to exploit.
When a user tries to connect to the company’s network, a procedure called the Three Way Handshake first needs to take place. First, the user requests input with a SYN packet. Then the server sends an acknowledgment response, a SYN-ACK. The user responds to this packet and the connection is established.
Syn Flood is when an attacker sends multiple connection requests from a fake IP. Thus, the server sends the SYN-ACK and waits for a response that never comes back, leaving the connection open. This can create a vulnerability within the system or, in sufficient quantity, occupy all of the server’s bandwidth and impede its activities.
There are three main types of Syn Flood attacks, as we’ll see below.
Direct
The simplest format, when the attack starts from a single spoofed IP. However, it is one of the rarest types, as this tactic exposes the criminal. As there is only one connection path to the source of the request, it is easier to track who carried out the attack.
counterfeit
Another path used in these attacks is to send multiple SYN packets from one IP address each. Thus, the criminal not only manages to overload the system, but is also able to hide his tracks. It is also more difficult to distinguish which requests are legitimate and which are part of this attack.
DDoS
DDoS-type attacks are more elaborate, often making use of a network of robots to carry out the attack. In many cases, the criminal installs malware on multiple computers and uses them to send the incoming request to the server. It is an even more effective and dangerous method, as the only IP address that appears in the request is that of the machine containing the malware, not the criminal.
How to protect against Syn Flood?
Faced with all these risks, it is important to take some steps to minimize the chances of success of this attack. Here are some security actions you can take.
Adjust the number of connections
In addition to there being a limit on the number of active connections between the server and different users, there is also often an arbitrary limit on the number of requests that can be queued. When this limit is reached, the server stops accepting new requests and the service stops.
To avoid this, you can establish criteria for adjusting this request limit, either automatically or manually. Thus, the server can withstand an attack and maintain its functioning.
However, this is not an ideal solution, as a larger attack will eventually consume all network capacity. It’s just a matter of who has more processing power.
recycle old connections
Eventually, your network will reach the point where it can no longer queue requests and the criminal will continue to send signals. In that case, the next step is to start “recycling” your connections, closing ports that have been open the longest to make room for new requests.
A common criterion here is the waiting time. If a connection takes too long to establish, then the server closes the port. In that case, legitimate requests must complete faster, or any space in the queue will be taken back by spoofed IPs.
Use Cookies Syn
In this method, instead of hogging the network with each request, the server clears the request as soon as the SYN ACK packet is sent, freeing its memory. If you receive a response, the connection is reestablished and the process continues normally. Thus, even in the event of an attack, there is no suspension of service.
The only problem with this method is that in some cases there is a small loss of data as part of the connection. However, it is still better than the alternative.
Use up-to-date protection software
As with any other type of attack, you can mitigate the risks of the Syn Flood by using digital protection software, particularly a firewall. This allows you to establish clearer criteria for identifying an attempted attack and preventing it from affecting your systems.
Whenever one of these malicious connections is identified, the system can temporarily block the originating IP, eliminating future attempts to establish a connection. In many cases, this is enough to mitigate its immediate impact.
What are the consequences of a Syn Flood attack?
There are two possible objectives for a Sun Flood attack: disrupting the server or creating a gateway. In the first case, the intention is to make the service inaccessible, which impacts work within the corporate environment and legitimate requests from customers.
The second case is even more dangerous. If the connection is not properly terminated, the criminal can use it to break into the company’s system and gain access to your data. It can also serve as a distraction, keeping IT staff busy with these requests while other areas are surreptitiously accessed.
To protect against Syn Flood attacks, the most important thing is to understand how they work and what their goals are. Only then can you define the best strategy to protect your network.
Do you want to get better information to keep your business network well protected? Then also check out our article on how to protect yourself against ransomware.
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