Thousands of federal computers attacked

Tens of thousands of federal government machines fell victim to a nationwide "denial-of-service" attack earlier this week on Microsoft Windows 95 and Windows NT computers, according to a government emergency response team member.

William Orvis, a team member of the governmentwide Federal Computer Incident Response Capability, estimated the attacks crashed "tens of thousands of machines," including thousands of machines at the Energy Department. Other federal agencies that reported being attacked included all NASA centers, several naval sites and the National Institutes of Health. Several universities were also hit.

"It wasn't specifically targeted at the federal government," Orvis said. "It was targeted at all Windows NT and Windows 95 boxes that were connected to the Internet."

Because many unsuspecting users may have simply rebooted their machines after what they assumed was just another desktop crash, more agencies were most likely affected than have reported the problem, he said.

The attackers exploited a vulnerability in a network port in older versions of the Windows 95 and Windows NT operating systems, said Christopher Klaus, chief executive officer of Atlanta-based Internet Security Systems. The hackers used an automated tool to launch an attack directed at as many machines as possible across the Internet, he said.

The existence of the vulnerability has been known for a couple of months, and in January Microsoft released a patch to plug it. However, many system administrators had failed to install the fix, Klaus said. In addition, a simple firewall misconfiguration could also allow for the unauthorized packets used to launch the attacks to clear a firewall without detection, he said.

Klaus said the attacks likely caused minimal damage unless a user had not saved a critical application that was open when the machine crashed.