When hackers nearly shut down eBay, Yahoo!, and several other large Internet sites a couple of months ago, they exploited an old security flaw, one well-known to network insiders. Now Felix Wu, a computer scientist at North Carolina State University, has devised software that would fix the problem without compromising the Internet's freewheeling structure.
In the recent assaults, hackers broke into networked computers and programmed them to overwhelm target Web sites with spurious traffic. Defending against such a barrage requires a coordinated effort by Internet service providers--but at present they have little incentive for cooperative vigilance.
Using Wu's program, an Internet server under attack can check with all its partnered servers to see which one forwarded the rogue traffic. That partner can then perform ever-finer internal checks until the culprit is identified. If the cooperating servers determine the attack did not originate with any of them, they can simply deny all access to noncooperating servers and so remain secure. Wu will release a free prototype of his software to the public later this year.