(LOIC) Low Orbit Ion Cannon is a network based Stress Testing Tool. Used in a common exploit known as Denial of Service Attacks or (DOS Attacks) aka Botnet Attacks.

What happens when a DOS Attack takes place? – Ping is a network tool used to send arbitrary packets of information over the wire to a web-server or web-based infrastructure and framework. Think of it as throwing pebbles into a pond where by creating ripples in the water. If enough pebbles are thrown in or they become bigger they eventually cause a wave so big that the pond overflows. This is also called a buffer overflow attack. A variant of this is heap and stack overflows.
An attack like this can be generated by several different packet protocol types. HTTP, TCP, and UDP Packets. The UDP protocol is the most commonly used one as UDP packets do not require a response back from the server for validation.
You may remember Mafia Boy a Canadian 16 year old back in 2001 who brought down Yahoo, Sprint, and other various websites via a Denial of Service Attack causing a combined $2.5 Million Dollars in loss over a 3 day time period. After his arrest congress proposed a bill that would hand out life sentences to anyone who initiated a Distributed Denial of Service Attack against any web-server because it is, and I quote “More economically crippling than mass genocide”.
The hacker group Anonymous recently us LOIC to launch a series of Denial of Service Attacks against the following organizations. The Department of Defense, HB Geary, Monsanto, RIAA, MPAA, FBI and other major firms who are playing a role in taking our civil liberties away, (mainly our first amendment) so they (Hollywood) can “Sell More Movies” by curving the use of P2P sharing sites.
~DynamicDesignz.net