Picture this: your local radio station runs a competition where the 15th caller will win something good. Suddenly 1,000 people are all on the phone trying to win the prize. While a radio station may easily handle 1,000 phone calls in a day, having 1,000 people all trying to call at once jams the switchboard.
We see the same kinds of traffic jams at rush hour during the work week, for major sports events, and at the supermarket just before a long holiday weekend when the shops may be closed for few hours.
Systems don’t much like crowds
If a system that is designed to handle a large volume of traffic spread out over a period of time suddenly has to handle it all at the same time things usually just break down.
Distributed Denial Of Service
Sometimes this kind of ‘traffic jam’ happens on the Internet. It may just be a random event, where suddenly a website gets very popular after a news report, but sometimes, just like a protest march, it’s deliberate.
There’s a thing called a Distributed Denial Of Service attack, otherwise known as a ‘DDOS’. The purpose of a DDOS attack is to bring a website or other Internet service to a standstill.
How a DDOS works
All you need to do, is to have thousands or hundreds of thousands, or even millions, of computers all try to visit the same website at the same time.
It’s easy to do if you have direct control over those computers.
This is where organised crime, or organised activist groups, come in.
The malware problem
There are millions of people out there whose computers are infected with viruses and other malware. Those infected, or ‘compromised’, computers become part of a botnet.
A botnet is simply a whole lot of computers networked together, probably through the Internet, and under the control of one person. The person controlling the botnet is likely to be part of a criminal group, such as a Mafia.
Roving gangs of computers
Often these botnets are used for sending out spam, but sometimes they’re used to attack certain targets.
So it was that recently some popular websites and services such as Twitter, Facebook, YouTube, and various blogging systems were subjected to a DDOS attack. The DDOS attack brought those services to a standstill.
Clogging the airwaves
It seems that one blogger in the Republic of Georgia had made himself unpopular with certain Russians. They launched a DDOS attack against the sites where the blogger was expressing his opinion. The attackers’ intent was to prevent him writing and speaking about the political situation.
By effectively clogging up his communication channels they were aiming to prevent him from airing his opinions.
As a side-effect, this attack caused outages and problems for all users of those systems — including you and me.
The hardest hit was microblogging site Twitter, which experienced an enormous system crash that blocked access for 45 million users worldwide for hours Thursday morning. Other sites, such as Facebook, were operational but experienced slowness and much longer load times.
It makes you think.
Still, I guess when Twitter and Facebook are ‘down’ we all have a bit more time on our hands …
Written by Miraz Jordan for, and reproduced from CommunityNet Aotearoa Panui, October 2009. This article has been modified for publication here.
Photo credit: Crowds of people pouring onto the platform at the Taipei Rapid Transit System’s Sun Yat-sen Memorial Hall Station on New Years Eve, 2006. Taken by User:Changlc.