What started out as a prank posting to comp.os.linux.advocacy yesterday has turned into one of the most significant viruses in computing history.
The creator of the virus, who goes by the moniker "Anonymous Longhair", modified the Melissa virus to download and install Linux on infected machines.
"It's a work of art," one Linux advocate told Humorix after he looked through the Tuxissa virus source code. "This virus goes well beyond the feeble troublemaking of Melissa." The advocate enumerated some of the tasks the virus performs in the background while the user is blissfully playing Solitaire:
Once the virus is activated, it first works on propagating itself. It has a built-in email harvesting module that downloads all the pages referenced in the user's Internet Explorer bookmarks and scans them for email addresses. Using Outlook, the virus sends a copy of itself to every email address it comes across.
After it has successfully reproduced, the virus begins the tricky process of upgrading the system to Linux. First, the virus modifies AUTOEXEC.BAT so that the virus will be re-activated if the system crashes or is shut down while the upgrade is in process. Second, the virus downloads a stripped-down Slackware distribution, using a lengthy list of mirror sites to prevent the virus from overloading any one server.
Then the virus configures a UMSDOS filesystem to install Linux on. Since this filesystem resides on a FAT partition, there is no need to re-partition the hard drive, one of the few actions that the Word macro language doesn't allow.
Next, the virus uncompresses the downloaded files into the new Linux filesystem. The virus then permanently deletes all copies of the Windows Registry, virtually preventing the user from booting into Windows without a re-install. After modifying the boot sector, the virus terminates its own life by rebooting the system. The computer boots into the Slackware setup programme, which automatically finishes the installation of Linux. Finally, the dazed user is presented with the Linux login prompt and the text, "Welcome to Linux. You'll never want to use Windows again. Type 'root' to begin..."
The whole process take about two hours, assuming the user has a decent Internet connection. Since the virus runs invisibly in the background, the user has no chance to stop it until it's too late.
The email message that the virus is attached to has the subject "Important Message About Windows Security". The text of the body says, "I want to let you know about some security problems I've uncovered in Windows 95/98/NT, Office 95/97, and Outlook. It's critically important that you protect your system against these attacks. Visit these sites for more information..." The rest of the message contains 42 links to sites about Linux and free software.
Slashdot is one of those links. "That could spell trouble," one Slashdot expert told Humorix. "Slashdot could fall victim to the new 'Macro Virus Effect' if this virus continues to propagate at its present exponential growth rate. Red Hat's portal site, another site present on the virus' links list, seems to be quite sluggish right now..."
Details on how the virus started are a bit sketchy. The "Anonymous Longhair" who created it only posted it to Usenet as an early April Fool's gag, a demonstration of how easy it would be to mount a "Linux revolution". Some other Usenet reader is responsible for actually spreading the virus into the wild. One observer speculated, "I imagine the virus was first sent to the addresses of several well-known spammers. The virus probably latched on to the spammer's email lists and began propagating at a fantastic rate. With no boundary to its growth, this thing could wind up infecting every single Net-connected Wintel box in the world. Wouldn't that be a shame!"
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