All DDoS Definitions
DDoS Testing Definition

CHARGEN Amplification

A CHARGEN amplification attack is a Layer 4 reflection and amplification vector, one of the volumetric classes a thorough DDoS test is built to exercise. CHARGEN (Character Generator Protocol) is a legacy diagnostic service on UDP 19 that replies to any packet with a stream of arbitrary characters. The attacker spoofs the victim's IP in a tiny request to exposed CHARGEN hosts, and each one floods the victim with a far larger response. The service has no modern use, yet it remains enabled on enough legacy devices to be abused as a reflector.

CHARGEN amplification: one byte in, a character flood out Attacker spoofs source IP as the victim tiny request to UDP 19 CHARGEN host legacy UDP port 19 answers any packet with a stream of characters endless character stream Victim buried in junk characters 1-byte request character-stream reply Amplification up to roughly 358 times the request size A test confirms no host still answers on UDP 19, that ingress filtering drops the spoofed sources, and where the flooded link sheds clean traffic. BlackNeuron™
CHARGEN amplification: a one-byte spoofed request to a UDP port 19 service returns an endless character stream that floods the victim

Why it matters in DDoS testing

CHARGEN reflection is a reminder that decades-old defaults still surface as live attack surface. Testing confirms whether any host inside the perimeter still answers on UDP 19, whether ingress filtering blocks the spoofed sources, and where the saturated link first drops legitimate traffic. The reflection mechanics common to these vectors are detailed in Understanding DDoS Attack Vectors.