A computer program carrying out some task on behalf of a user,
such as delivering a Web page or sending email
messages. Computers on which these server applications are found are also
called servers.
Servers have often been the focus of computer security
attacks. For example, on March 8, 2005, a security researcher announced in an
advisory that Microsoft CorporationÂ’s newest operating systems are vulnerable
to Denial of Service (DoS)
attacks. In particular, researcher Dejan Lavaja said that Windows Server 2003
and XP Service Pack 2 (with the Windows Firewall not on) could suffer from LAND
attacks—remote DoS incidents created when a packet
is sent to a computer on which the source host/port is the same as the
destination host/port. Using reverse-engineering tools, this researcher
discovered that just one LAND packet transmitted to a file server could result
in “frozen” Windows Explorers on all the workstations connected to that server.
In fact, warned Lavaja, because of this vulnerability the network could totally
collapse.
Soon thereafter, however, a spokesperson for the Microsoft
Corporation said that although the vulnerability exists, the adverse impact of
such an attack would result only in the computerÂ’s running sluggishly for a
brief period. Users were cautioned to filter traffic with the same IP source and
destination address.
See Also:
Denial of Service (DoS); Electronic Mail or Email; Host; Node; Packet.
Naraine, R. Old-School DoS Attack Can Penetrate XP SP2. [Online, March 8, 2005.] Ziff Davis Publishing Holdings
Inc. Website. http://www.eweek.com/article2/
0,1759,1773958,00.asp.
