SYN Flood Attack is a type of Denial of Service (DoS) attack in which an attacker sends a large number of SYN (synchronise) requests to a target server in an attempt to overwhelm it, causing the server to become unresponsive or crash.
How It Works:
- The attacker sends numerous SYN packets (part of the TCP handshake) to the target server.
- The server responds with SYN-ACK packets, waiting for the final ACK to complete the handshake.
- Since the attacker does not send the final ACK packet, the server's resources are tied up waiting for responses, exhausting its ability to handle legitimate connections.
- As the server runs out of resources, legitimate users are unable to access the service.
Common Use Cases:
- Disrupting Services: SYN flood attacks are used to disrupt access to websites or online services by overwhelming their servers.
- Targeting Weak Servers: Attackers may use SYN floods to target servers with insufficient capacity to handle high volumes of incoming requests.
Effects of SYN Flood Attacks:
- Service Downtime: Servers or services may become slow or completely unavailable, impacting users and business operations.
- Resource Exhaustion: The attack consumes server resources, potentially leading to system crashes or slow performance.
Mitigation Techniques:
- Firewalls and Filters: Firewalls can detect and block SYN flood traffic.
- Intrusion Detection Systems (IDS): IDS can identify abnormal traffic patterns that indicate an attack.
- Rate Limiting: Servers can limit the rate of incoming requests to mitigate SYN floods.
- SYN Cookies: A technique where the server doesn't allocate resources until the handshake is completed, preventing resource exhaustion.
In summary, SYN Flood Attacks are a malicious attempt to overload a server by sending excessive connection requests, leading to service disruptions or downtime. Proper security measures are needed to prevent or mitigate their impact.
