Fraggle Attack
Definition
A Fraggle attack is a type of denial-of-service (DoS) attack that floods a victim with UDP traffic by sending spoofed UDP packets to a network broadcast address, causing multiple systems to reply simultaneously to the target.
Examples
- An attacker sends spoofed UDP packets to port 7 (Echo) on a broadcast address, causing all devices on that network to respond to the victim.
- A misconfigured network allows a Fraggle attack to overwhelm a server with a flood of reflected UDP traffic.
Overview
A Fraggle attack is a form of denial-of-service (DoS) attack that uses UDP traffic instead of ICMP to overwhelm a target system. It works by sending UDP packets with a spoofed source IP address — that of the victim — to the broadcast address of a network. All the devices on that network then reply to the spoofed IP, flooding the victim with responses.
While similar in nature to the more well-known Smurf attack, which uses ICMP Echo Requests, the Fraggle attack uses UDP Echo (port 7) or Chargen (port 19) services to generate its flood. These protocols are often overlooked in basic security settings, making networks with misconfigured or legacy devices particularly vulnerable. The attack is simple in concept but can have severe effects if amplification is achieved.
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