Netsky.P Spreads Through Ancient Security Hole

By Larry Seltzer  |  Posted 2004-03-22 Print this article Print

A new variant of the worm utilizes an Internet Explorer bug patched almost three years ago.

McAfees Avert labs is reporting that a new variant of the Netsky worm, Netsky.P, is spreading quickly. Both McAfee and Trend Micro Inc. rate Netsky.P as a "medium" threat and Symantec Corp. has rated it a "2" (for "Low," on a scale of 1 to 5). This is the first new variant of Netsky seen in about a week, a long hiatus for recent times. This new variant is very much like other Netsky versions with two differences, according to Vincent Gullotto, vice president of the McAfee Avert Virus and Vulnerability Emergency Response Team. The initial seeding of the worm, referring to the initial group of users to whom the virus author distributed it, appears to have been in Australia. Its not clear whether or how this would facilitate spreading of the worm, but it is unusual.

The other interesting and unusual characteristic of this worm is that is utilizes a very old vulnerability in Internet Explorer, the Incorrect MIME Header (MS01-020) bug. This bug, patched almost three years ago, allowed a hostile HTML e-mail to execute arbitrary code if viewed in the preview pane of a mail client.

Once very much in vogue among virus writers, it has fallen into disuse in recent times. Its not possible to know if Netsky.P is spreading because of the MS01-020, but Gullotto said it is probably a "contributing factor."

Like other Netsky variants, this one spreads mainly through a built-in SMTP engine to e-mail addresses harvested out of the users files. It varies the subject line and body of the message, and the from: address will also be randomly selected from addresses harvested from the user. The attachment uses a variety of executable and .ZIP file names.

Check out eWEEK.coms Security Center at for security news, views and analysis.
Be sure to add our security news feed to your RSS newsreader or My Yahoo page:  
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.

Submit a Comment

Loading Comments...
Manage your Newsletters: Login   Register My Newsletters

Rocket Fuel