Skip to content

TCP SYN ACK Flood

Jump to bottom
yukı edited this page Aug 24, 2023 · 4 revisions

Introduction:

The SYN-ACK flood attack is a type of Denial of Service (DoS) attack that targets the TCP handshake process by overwhelming a victim server or network with a flood of SYN-ACK packets. This attack exploits the vulnerabilities in the TCP protocol, causing resource exhaustion and rendering the system unresponsive to legitimate traffic.

Understanding SYN-ACK Flood Attacks:

In the TCP handshake process, after receiving a SYN packet from a client, the server responds with a SYN-ACK packet to acknowledge the request and initiate the connection establishment. SYN-ACK flood attacks exploit this mechanism by flooding the victim server with a massive volume of SYN-ACK packets without completing the handshake process.

During a SYN-ACK flood attack, the attacker sends a barrage of SYN-ACK packets to the victim server using spoofed or randomly generated source IP addresses. The server allocates resources to establish the connections, but since the attacker does not respond to the server's ACK packets, the connections remain in an unfinished state, consuming server resources. As a result, the victim server becomes overwhelmed, leading to service disruptions or complete unavailability.

Implications of SYN-ACK Flood Attacks:

SYN-ACK flood attacks can have severe consequences for targeted systems and networks, including:

  • Denial of Service (DoS): The excessive volume of SYN-ACK packets floods the victim server, depleting its resources and rendering it unable to handle legitimate traffic. This results in a denial of service for legitimate users, leading to business disruptions, financial losses, and reputational damage.

  • Resource Exhaustion: SYN-ACK flood attacks cause significant resource exhaustion on the victim server. The server allocates memory, CPU cycles, and network bandwidth to handle the incoming SYN-ACK packets, leading to performance degradation, system crashes, or complete unresponsiveness.

  • Connection Backlog: As the victim server struggles to establish connections due to the flood of SYN-ACK packets, legitimate connection requests may be delayed or dropped. This backlog of pending connections further exacerbates the impact on the server's performance and user experience.

How the script deals with that:

  • Rate-Limit.
  • Automatic TCP SYN Cookies.
  • Anti-Spoofing.
  • Stateful Packet Inspection.
Clone this wiki locally