This weekend marks the 20th birthday of the internet worm, which Robert Tappan Morris created on November 2nd 1988.
The Morris Worm' changed the face of internet security forever, containing a bug which allowed it to self-replicate in a single machine multiple times, causing thousands of computers to grind to a halt.
It was designed to propagate across Unix systems and exploited vulnerabilities to gain entry. However, due to a design flaw, the Worm went for far more propagation attempts then were necessary and caused the targeted machines to slow dramatically or shut down.
Morris said he simply created the worm to gauge the size of the internet by self-replicating, and didn't intend to cause any damage. He didn't serve any jail time, but he was sentenced to community service and probation.
It led to the creation of other more visible worms which were aimed at causing damage such as the SQL slammer which attacked vulnerabilities in Microsoft SQL Server and the ILOVEYOU worm which arrived in e-mail inboxes and caused billions of pounds worth of damage.
Nowadays worms and their writers do not want to cause such public damage, and propagate through systems like Facebook and Google with the intention of infecting other systems through means such as video. Desktop systems are left compromised, transmitting keystroke logs and credit card numbers captured from victims
