Next-Generation Nachi Worm Offers Political Message

By Larry Seltzer  |  Posted 2004-02-12 Print this article Print

The Internet is fertile with new and modified worms, but the most interesting is the next-generation of Nachi. The vigilante worm has gone strangely political.

"May you live in interesting times" goes the old curse. Times are interesting indeed in the world of computer security, especially this week. Every day brings another major worm or attack, maybe two, and the outlook looks even worse. The last few days have shown remarkable fertility among computer worms, as new variants of MyDoom arrived on the Internet. A new worm on Wednesday began crawling the AOL Instant Messenger network. And a new variant of the vigilante worm Nachi arrived on Thursday. By the time you read this, all of the above may be old news, overtaken by even newer variants doing crazier things.
Of course all of it is less scary than Microsofts announcement this week of a Link security hole in Windows that, as with the Blaster incident from last year, could allow for remote network infiltration without user action.

The most interesting, to my mind, is Nachi.B also known as Welchia.B. Some may remember the A version of this one that came out last summer in the wake of Microsofts DCOM RPC vulnerability. Nachi.A spread through the DCOM RPC hole and then tried to download and install the patch to fix the hole. It also attempted to remove the Blaster worm, the most significant malicious exploit of that particular vulnerability.

Anyway, Nachi.B attempts to exploit these same holes and some others in order to spread itself. It then attempts to remove the MyDoom.A and MyDoom.B worms and undo some of the damage they cause, such as the overwritten HOSTS file. Nachi basically writes a blank one. Finally, it attempts to download and install a Microsoft patch for a buffer overrun in the Messenger service.

So its trying to be helpful. Or so it would seem. However, remember that Nachi.A was funny news at first, but it quickly became for many corporations a bigger problem than Blaster. I note that its still out in the wild. Nachi.B could easily prove to be as bad. Some persons no doubt will spread it intentionally because its a "good" worm. Next Page: Decoding Nachi.Bs Political Message.

Larry Seltzer has been writing software for and English about computers ever since—,much to his own amazement—,he graduated from the University of Pennsylvania in 1983.

He was one of the authors of NPL and NPL-R, fourth-generation languages for microcomputers by the now-defunct DeskTop Software Corporation. (Larry is sad to find absolutely no hits on any of these +products on Google.) His work at Desktop Software included programming the UCSD p-System, a virtual machine-based operating system with portable binaries that pre-dated Java by more than 10 years.

For several years, he wrote corporate software for Mathematica Policy Research (they're still in business!) and Chase Econometrics (not so lucky) before being forcibly thrown into the consulting market. He bummed around the Philadelphia consulting and contract-programming scenes for a year or two before taking a job at NSTL (National Software Testing Labs) developing product tests and managing contract testing for the computer industry, governments and publication.

In 1991 Larry moved to Massachusetts to become Technical Director of PC Week Labs (now eWeek Labs). He moved within Ziff Davis to New York in 1994 to run testing at Windows Sources. In 1995, he became Technical Director for Internet product testing at PC Magazine and stayed there till 1998.

Since then, he has been writing for numerous other publications, including Fortune Small Business, Windows 2000 Magazine (now Windows and .NET Magazine), ZDNet and Sam Whitmore's Media Survey.

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