Pentagon dodges virus threat

The Pentagon took the Code Red worm very seriously

By BBC News Online's Kevin Anderson in Washington

The Pentagon has restored access to its websites, after having pulled the plug on its public-facing sites due to the Code Red worm computer threat.

The dot.mil sites were unavailable to the public from Friday morning until Tuesday afternoon, said Defence Department spokeswoman Susan Hansen. Military personnel were still able to access the sites from other computers on the dot.mil domain.

"We temporarily blocked public access because we do not want to propagate the virus," she said.

Defence Department network administrators patched their servers before restoring public access, and Ms Hansen said that the Pentagon was not seeing any additional activity from the worm.

And she said that impact of the virus on military computers was minimal.

The US Defence Department is the world's largest user of computers, with some 10,000 networks.

White House targeted

The Code Red worm spread quickly and it infected hundreds of thousands of internet servers.

Security experts with eEye Digital Security said that the worm could attempt to infect roughly a half a million internet addresses a day.

The worm exploits a vulnerability in internet server software from Microsoft on the companies NT 4.0 and Windows 2000 operating systems.

The worm attempted to launch an attack on the White House's website

The vulnerability was discovered by eEye a month ago, and the firm performed an analysis of the Code Red worm.

For English websites, the worm replaces sites' homepage with the text "Hacked by Chinese."

The worm's ultimate purpose was to launch a denial of service attack against the White House website.

In a denial of service attack, infected computers attempt to flood a website with traffic, rendering it unable to respond to legitimate requests.

But White House web administrators foiled the attack by moving the site to a new address.

The worm's activity dropped off after the attempted attack on the White House site, but security experts say that the worm will attempt to infect computers again on 1 August.

And a variant of Code Read has already been discovered - more stealthy and faster spreading than the original.