👉 Overview
👀 What ?
The Echo Protocol is a service in the Internet Protocol Suite defined in RFC 862. It operates on port 7 both in the TCP and UDP services. The protocol was originally designed for testing and measurement of round-trip times and network bandwidth.
🧐 Why ?
Understanding the Echo protocol is important for cybersecurity professionals and pentesters as it can be used as a vector for security attacks. Attackers can use this protocol to cause a Denial of Service (DoS) attack by causing an infinite loop between two Echo servers, known as an 'Echo Storm'. Therefore, it is crucial to understand this protocol to protect systems and networks effectively.
⛏️ How ?
To pentest the Echo protocol, start by scanning the network to identify any systems that have port 7 open. Tools such as Nmap can be used for this purpose. Once identified, you can then use various techniques to test the vulnerability of the system. For instance, you can try to cause an Echo Storm by sending a large amount of echo requests to the system. Always remember to carry out such tests in a controlled and legal environment.
⏳ When ?
The Echo Protocol has been a part of the Internet Protocol Suite since its inception in the 1980s. However, due to its potential for misuse, it is often disabled on modern systems. Despite this, it is still important to check for this potential vulnerability when conducting a pentest.
⚙️ Technical Explanations
The Echo Protocol operates by simply sending back any data it receives. This makes it useful for measuring the time it takes for data to travel to a specific destination and back, known as the round-trip time. However, this simplicity also makes it vulnerable to misuse. An attacker can send a large amount of data to an Echo server, causing it to become overwhelmed and unresponsive. This is known as a Denial of Service (DoS) attack. Additionally, an attacker can cause an infinite loop between two Echo servers by making each server send its data to the other. This is known as an 'Echo Storm' and can also result in a DoS.