John Kenneth Schiefer, 26 from Los Angeles has pleaded guilty to four charges of wiretapping and fraud.  Schiefer worked as an IT security consultant but then illegally took control of over 250,000 PC’s by infecting them with his own malicious software.

Once the PC’s were infected they were fully under his control, which allowed him to then capture and re-use login details for PayPal.  The amount of money stolen from the victim’s has not yet been fully calculated.

A collection of infected PC’s is often called a “Botnet” and is often used to send out spam emails.  Schiefers Botnet of 250,000 PC’s is relatively small, with some Botnets thought to contain millions of infected PC’s.

Once a hacker has built up a large Botnet they often rent time out on the PC’s to other criminal gangs – usually to send out spam emails.  It is these Botnets that can quickly overrun the Internet with millions of spam messages.  With simple precautions and up-to-date virus scanners (ClearMyMail blocks all virus emails) the number of PC’s available to these gangs would drastically drop.