A Canadian teenager accused of immobilizing some of the Internet’s most popular Web sites through a denial-of-service (DoS) attack in February has offered an innocent plea in a Montreal courtroom.

The 16-year-old Montreal-area high-school student, who allegedly operated under the screen name of “MafiaBoy,” was charged with 54 counts of illegal access to computers, said Staff Sgt. Jean-Pierre Roy of the Royal Canadian Mounted Police’s computer investigation and support unit. Under Canadian juvenile law, the identity of the suspect cannot be released.

The teen faces dozens of new charges of hacking and mischief in addition to those offences he was indicted for in April. Those earlier charges include two counts of mischief to data on the Web sites of CNN and the more than 1,200 Web sites it was hosting on between Feb. 7 and 14. The boy allegedly pulled together a series of computers and used them to send vast amounts of data to the CNN site, causing the system to fail.

The teen was also hit with two charges each for accessing Yahoo Inc., Amazon.com Inc., Dell Computer Corp., eBay Inc. and Outlaw.net, Roy said.

During February’s well-publicized distributed DoS attacks, visitors to the Web sites of those Internet giants were locked out for hours as the sites lay crippled under the DoS onslaught.

Authorities say the teen launched his attack by using computers from various American universities as “zombies” to flood the popular Internet sites with bogus data packets, overloading access to them.

Since his arrest, the teen has been released on bond with several non-academic computer access and proximity restrictions imposed on his release.

His next court appearance is Sept. 28, where a trial date will be set. If convicted, the youth faces a maximum of two years in a juvenile facility.