"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)..."