A new worm now "in the wild" has the potential to shut down Windows platforms and make the operating system permanently unusable.
Computer Associates International discovered the worm, Win32/Melting.worm, Tuesday, when customers started to find it in their e-mail systems, said Narender Mangalam, director of security solutions at CA. So far, it has hit some Fortune 1,000 software companies, he said.
"The risk level is moderate, and it hasn't caused too much damage because we believe we've caught it in time," Mangalam said.
The Melting Worm is unleashed through Microsoft's Outlook running on Windows 95, 98, 2000 or NT, according to CA. Once launched, the worm puts a copy of itself into a Windows directory as MeltingScreen.exe and remains in memory. Files with .exe extensions in a system's Windows directory are renamed with .bin extensions.
As the worm renames files, including ones critical to operating Windows, these changes may render the operating system useless.
The worm also starts to e-mail itself to all the names in a victim's Outlook address book and randomly executes other .exe files, Mangalam said. This potentially can take down a company's e-mail system.