Fighting malware and spam

DoS

Attack attempting to crash system or software

A Denial of Service (DoS) attack is an attempt to prevent a piece of software, system, webserver or website from functioning.

Simple DoS attacks often take the form of an exploit, taking advantage of a vulnerability to crash software or a system. Anti-malware or anti-spam software may be caused to overload or shut down, for example, to force the filter to allow malware or spam through to the end users.

Multiple attackers combining to perform a DoS attack by overwhelming force of numbers is known as Distributed Denial of Service, or DDoS.

DoS should not be confused with DOS, a family of operating systems which ran many early computers, of which the most famous is MS-DOS, the basis of early versions of Windows.