No one has confirmed that these tools, or even something like them, have been used in any of the recent high-profile incidents. Many security analysts are betting that a single individual or coordinated group is responsible for the incidents of the last 48 hours. But that doesn't mean that other, unrelated attacks aren't lurking around the corner. These tools are easy to download from the Net, experts say. The FBI already said it has found traces of the attack tools widely distributed on potential host networks, raising the possibility of a new wave of outages.
Network administrators say there are few sure-fire defenses against such attacks.
Yet industry analysts said they see little evidence of a crippling threat to Internet commerce in the long term. This week's strikes were relatively brief, presumably to help keep the perpetrators from being easily caught. In addition, blitzes of the scale that brought down Yahoo are still thought to be difficult to organize. But in that case, the odds of somebody noticing go up a lot. Online toy seller eToys, for example, was targeted last month by Net users upset over the company's legal efforts to shut down the domain name of an art group going by the name of etoy.