Zotob Proves Patch Management Isnt Enough

By Larry Loeb  |  Posted 2005-08-17 Print this article Print

Opinion: The Zotob fiasco is a harbinger of things to come, namely "Zero-Day" malware.

It may be just schadenfreude, but nothing makes me chuckle more than seeing media outlets get nailed by Windows malware. The sense of barely suppressed outrage that CNN talent exhibited on air over the fact that their systems were attacked by Zotob (and the variants) was a hoot. (ABC and The New York Times were hosed as well.) It was as if their machines were too good to be infected, and they werent the sort of people who got this stuff. Malware is the new social disease.
Microsoft actually (and it pains me to say this) acted responsibly over Zotob. It identified the vulnerability and gave the patch at the same time.
Even though it was part of the 30-day cycle it likes to use for most patches, the information it got out seems to have averted the potential of apocalypse. Indeed, the malware does not seem to be widespread as of this date. Whether thats just good luck, the lack of networked Windows 2000 (the worms main target system though patches are available for later OSes), or speedy patching remains to be seen. Just having the patch doesnt mean you have the solution. Any responsible enterprise IT guy is going to have to test the patch before deployment. That takes time. Then, you have to deploy it over the enterprise, and that takes some more time. So, its no surprise that organizations got caught with their pants down on this. You cant turn a battleship on a dime. Click here to read more about Zotob from columnist Steven J. Vaughan-Nichols. Some of the "best practices" to remedy this situation (shut down port 445, patch, and eliminate NULL sessions) can have untoward consequences. For example, it has been recommended that NULL sessions be disabled, since this is one of the propagation mechanisms. But some server roles may require administrators to enable NULL session functionality, such as legacy domain controllers, Microsoft Exchange servers, Microsoft SQL Servers, etc. But restrictive action has its consequences as well. If you enable blocking of anonymous share enumeration (so that there are no NULL sessions), by setting HKLM\SYSTEM\CurrentControlSet\Control\Lsa\restrictanonymous to "1", you will also break Windows Networking. The browser subsystem needs this to enumerate servers in Network Neighborhood. Your users will complain, and loudly. The malware writers are agile and quick. To read more about the appearance of Zotob, click here. The fact that the first exploits showed in the wild three days after the announcements of it means that we are edging closer to the dreaded "Zero Day" kind of malware: the stuff that shows up on or before the patches are ready. The variants are getting smart, too. While the original malware uses port 445 to download the actual viral code, one Zotob variant propagates by e-mail. Thus, a defense against one vector wont work for the other. Indeed, the ways Zotob functions may evade normal virus scans entirely. For example, you cannot rely on TCP/33333 FTP service detection to identify compromised systems, as this port is not used consistently in later bot Zotob variants. The SANS Internet Storm Center has gone from InfoconYellow over the weekend to Infocon Green, reflecting the current net status. It may well be that Zotob is just the front-runner of various exploits that will use this vulnerability, which may change how SANS view things. But as of Wednesday, the only technique that seems to work is to patch, and then defend your systems in depth. The vectors of infection will undoubtedly change in a most Darwinian fashion. Larry Loeb was consulting editor for BYTE magazine and senior editor of WebWeek. He serves as a subject matter expert for the Department of Defenses Information Assurance Technology Analysis Center, and is on the American Dental Associations WG-1 and MD 156 electronic medical records working groups. Larrys latest book is "Hackproofing XML," published by Syngress (Rockland, Mass.). If youve got a tip for Larry, contact him at nospamloeb-pbc@yahoo.com. Check out eWEEK.coms for the latest security news, reviews and analysis. And for insights on security coverage around the Web, take a look at eWEEK.com Security Center Editor Larry Seltzers Weblog.

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