With the spread of the internet, the threat of cyberattacks is becoming increasingly serious. Among them, DDoS attacks are widely known as attacks targeting websites and online services, and their methods are becoming more sophisticated. In recent years, there has been an increasing trend of “GRE Flood attacks,” which are more difficult to detect and defend against than conventional DDoS attacks.

The Growing Threat of GRE Flood Attacks: Understanding the Mechanics and Countermeasures

What is a GRE Flood Attack?

A GRE Flood attack is a type of DDoS attack that exploits the GRE (Generic Routing Encapsulation) protocol. GRE is a technique used to tunnel data between different network protocols. Attackers use this GRE protocol to send a large number of GRE packets to the target server, flooding the network bandwidth and disrupting service.

How GRE Flood Attacks Work

  1. Botnet Construction: The attacker controls a large number of computers infected with malware to form a botnet.
  2. Attack Launch: A massive number of GRE packets are sent from the botnet to the target server.
  3. Network Saturation: The target server and network devices are overwhelmed with processing the massive amount of GRE packets, depleting resources.
  4. Service Disruption: Legitimate user access is blocked, and the service becomes unavailable.

Dangers of GRE Flood Attacks

  • Difficult to Detect: GRE packets are easily disguised as normal traffic, making it difficult to detect the attack.
  • Difficult to Defend Against: Due to the diverse and massive nature of the attack traffic, it is difficult to completely defend against.
  • Significant Damage: It can completely shut down the target service, seriously impacting business.

Countermeasures Against GRE Flood Attacks

To protect your system from GRE Flood attacks, it is necessary to take multi-layered defense measures.

  1. Traffic Filtering: Configure access control lists (ACLs) on firewalls and routers to restrict the GRE protocol and block suspicious traffic.
  2. Rate Limiting: Limit the transmission rate of GRE packets from specific IP addresses to mitigate the impact of attacks.
  3. DDoS Protection Services: Utilize DDoS protection services offered by specialized security vendors to counter sophisticated attacks. These services detect and automatically block attack traffic, protecting the system.
  4. Network Monitoring: Continuously monitor network traffic to establish a system that can detect abnormal traffic early on.

Measures Companies Should Take

  • Strengthen Security Measures: Apply the latest security patches and implement/strengthen security measures such as firewalls and intrusion detection systems.
  • Employee Education: Conduct security awareness training for employees to raise awareness of phishing scams and malware infections.
  • Develop an Incident Response Plan: Clarify response procedures in case of an attack and establish a quick recovery system.

GRE Flood attacks are a serious threat to businesses. However, by taking appropriate countermeasures, damage can be minimized. Refer to the measures introduced above and strengthen your security measures to protect your company’s systems.