"Public networks like the Internet are dangerous places. Anyone who has a computer attached to the Internet (even transiently) understands these dangers. Attackers can exploit insecurities to gain access to a system, to obtain unauthorized access to information, or to repurpose a computer in order to send spam or participate in attacks on other high-profile systems (using SYN floods, as part of a Distributed Denial of Service attacks).
"Distributed Denial of Service (DDoS) attacks are orchestrated from many systems across the Internet (so-called zombie computers) to consume resources on the target system and make it unusable for legitimate users (exploiting TCP's three-way handshake)..."
