Only a very small percentage of Mac users are vulnerable to the virus, but for them the danger of file destruction is a real threat, according to Carey Nachenberg, chief researcher at Symantec Corp.'s (Nasdaq:SYMC) AntiVirus Research Center.
Nachenberg said Macs must meet a narrow set of criteria to be vulnerable to the computer virus, which has spread across the world in a matter of days through e-mail traffic. A Mac must be connected to an infected Windows computer over a file-sharing network, he said, or the malicious e-mail file must have been opened through a PC-emulation program.
In addition, he said, the names of the vulnerable Mac files must bear Windows-compatible file-name extensions, such as .doc, .ppt, .hsm, .xls and others.
"Generally Mac users are absolutely safe because this is a Windows 32-bit virus," Nachenberg said, meaning it requires a Windows 32-bit operating system -- such as Windows 95, 98 and NT -- to operate. "But yes, there are some Macintosh users who are at risk."
Mixed networks vulnerable
One Mac user who fell victim to the worm virus is Scott Champion of Chicago, whose advertising firm, The Champion Agency, runs a mixed network of two Power Mac G3s and a PC running Windows 95.
Champion said the computers are connected on an AppleTalk network, and many of the file names have Windows file-name extensions to accommodate PC customers.
The worm virus apparently came into the office through e-mail on the Windows machine, he said, and proceeded to destroy files across the network by reducing their file sizes to 1 Kbyte each -- effectively wiping them clean of data.
"I've got dozens and dozens of 1-K files," Champion said. "Fortunately I've got them backed up, so it's not a tragedy."
So far, though, most Mac users seem to be unaffacted by the latest virus, although there are a few concerns. Even if they don't suffer data loss, Macs reportedly may be able to pass the virus via e-mail, and it's unclear whether a ZIP file decompressor opens the door to trouble. It's similarly unclear whether Mac users can activate the virus when opening e-mail through PC-emulation software.
Several anti-virus developers have posted software updates to catch the virus before it does any damage, including Symantec Corp. and Network Associates Inc. (Nasdaq:NETA).
