The ICMP Echo protocol (usually known as "Ping") is mostly harmless. Its main security-related issues are: ... There used to be security holes in some widespread TCP/IP implementations, where a malformed Ping request could crash a machine (the "ping of death").

Is ICMP secure?

Many network administrators feel that ICMP is a security risk, and should therefore always be blocked at the firewall. It is true that ICMP does have some security issues associated with it, and that a lot of ICMP should be blocked. But this is no reason to block all ICMP traffic!

What is ICMP security?

An Internet Control Message Protocol (ICMP) flood DDoS attack, also known as a Ping flood attack, is a common Denial-of-Service (DoS) attack in which an attacker attempts to overwhelm a targeted device with ICMP echo-requests (pings).