A memcached distributed denial-of-service (DDoS) attack is a type of cyber attack that exploits the memcached system to flood a targeted victim with an overwhelming amount of internet traffic. Memcached is a high-performance, distributed memory caching system commonly used to speed up dynamic web applications by caching data and objects in RAM. However, when memcached servers are improperly configured to listen on the public internet and use the UDP protocol, they can be exploited as reflectors and amplifiers in DDoS attacks.
In a memcached DDoS attack, the attacker sends spoofed requests to a vulnerable UDP memcached server with the source IP address forged to that of the target. The memcached server, believing the requests are legitimate, responds to the target’s IP address with a significantly larger payload. Due to the amplification capabilities of memcached servers, the volume of the response can be many times larger than the original request, resulting in a substantial increase in traffic directed at the victim.
Key characteristics of memcached DDoS attacks include:
- Amplification: The attacker leverages the memcached server’s ability to send large responses to small requests, amplifying the volume of traffic directed at the target.
- Reflection: The attack involves reflecting traffic off memcached servers to the target, obscuring the attacker’s identity.
- Spoofing: The attacker spoofs the source IP address of the requests to match the target’s IP address, causing the memcached server to send the response to the victim.
To mitigate the risk of memcached DDoS attacks, it is crucial for organizations to secure their memcached servers by disabling UDP support if not needed, binding the servers to a local interface or using a firewall to block public access, and implementing rate limiting and traffic filtering measures to detect and block malicious traffic. Additionally, regular monitoring of network traffic can help identify and respond to potential DDoS attacks promptly.
