In one case, more than 60 self-styled "computer security enthusiasts" have banded together to strike out against Palestinian and Afghani sites, according to a statement released Thursday by admitted online vandal The Rev and a group calling itself The Dispatchers.
"We, as a group, of individuals, have taken a stand, armed with technology...to disable our target in every method possible," the group said in the statement. "As of September 11th, 2001, we have united to fight back and to show that we will not tolerate...this anymore."
The message was sent by The Rev, who defaced in February the financial quoting service used by The New York Times
However, the Chaos Computer Club, a group of computer aficionados in Germany, learned of the plan and roundly criticised the call to arms.
"The Chaos Computer Club strongly condemns this appeal and asks the public to ignore said appeal and similar ones," the group said in a statement. "Being a galactic union of hackers, we simply cannot imagine (dividing) the world into good and bad at this moment and use--of all reasons--religion as a criterion for such a segregation."
Jens Ohlig, spokesman of the Chaos Computer Club, added in the statement: "We face this power of destruction and feel helpless. However, we believe in the power of communication--a power that has always prevailed in the end and is a more positive force than hatred."
The vigilante reaction by online vandals does not come as a surprise to authorities.
The FBI's National Infrastructure Protection Centre (NIPC) issued an advisory Friday warning companies of increased hacking activity in the name of "patriotism" and of the spread of computer viruses that label infected files with names that relate to Tuesday's tragedies.
"The NIPC reiterates that (such) conduct is illegal and punishable as a felony, with penalties extending to five years in prison," the warning said. "Those individuals who believe they are doing a service to this nation by engaging in acts of vigilantism should know that they are actually doing a disservice to the country."
After the terrorist attacks on the World Trade Centre and the Pentagon, the NIPC on Tuesday initially warned companies to beware of an increase in online activity but offered no specific details. "Infrastructure owners and operators should be at a heightened state of alert and should implement appropriate security measures--both physical and cyber," the NIPC said.
Several other known online vandals have also defaced sites this week, and an old computer virus has been renamed WTC, apparently in response to Tuesday's terrorist attack.
Fluffi Bunni, a habitual Web site defacer who has claimed responsibility for digitally tagging several open-source sites, broke into the DNS (domain name system) server of a Web hosting company, Newsbytes.com reported Friday.
By modifying the DNS entries, visitors to thousands of site were redirected to a page declaring: "Fluffi Bunni goes JIHAD."
Also on Friday, the NIPC warned that at least one person had renamed a computer virus--the LifeStages virus--to WTC.txt.vbs in an apparent attempt to cause it to spread further.
