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As spread of the dangerous new W32.Blaster Windows worm slows, attention is shifting to Microsoft's efforts to help its customers patch vulnerable systems--and some complain of inadequate protection and unreliable information about securing their PCs.

W32.Blaster first appeared on the Internet Monday and quickly spread worldwide. It infected hundreds of thousands of computers and caused disruptions on corporate and university networks, as well as on home computers.

Blaster targets a Windows component for handling Remote Procedure Call protocol traffic called the Distributed Component Object Model interface, and affects almost every supported version of Windows.

As of Wednesday, Blaster had infected more than 225,000 systems worldwide, according to Albert Huger, senior director of engineering at Symantec Security Response.

A new variant of Blaster also appeared Wednesday and seemed to be spreading, according to antivirus companies.

Microsoft Reconsiders

Microsoft issued a software patch for affected systems in July and urged its customers to apply the patch as soon as possible to protect against attack.

At that time, the company also provided a number of workarounds for companies that were unable or unwilling to deploy the patch. However, those workarounds as well as Microsoft's initial statements about which Windows systems the patch covers have come under increasing scrutiny as the Blaster worm spreads.

Microsoft acknowledged Wednesday that a workaround to disable DCOM on Windows 2000 systems that was provided in its security bulletin does not work for systems running certain flavors of Windows 2000.

"We have verified that there is a non-security related bug that makes the (workaround of disabling DCOM) ineffective on machines running the Windows 2000 gold version or service packs one and two," says Stephen Toulouse, security program manager at Microsoft.

Workaround Flawed

The workaround required Windows users or administrators to change a Windows configuration setting to disable DCOM.

However, changing that setting has no effect on DCOM for Windows 2000 servers running the original (or "gold") version of that software or with Service Packs 1 and 2 installed, according to Marc Maiffret, chief hacking officer at eEye Digital Security.

Microsoft also failed to explain that Windows systems must be restarted to ensure protection after the configuration change, Mailfret says.

System administrators who used the DCOM workaround as a fast and efficient way to protect systems while patches were being deployed thought they were protected, but may are still vulnerable, Maiffret adds.

So far, there have been no reports of infections due to the confusion over disabling DCOM, according to Russ Cooper, surgeon general of TruSecure and moderator of the popular discussion list NTBugtraq.

Also, applying certain patches for Windows 2000 did enable users to properly disable DCOM, Cooper adds.

Cooper recommends affected users disable DCOM because it is the most effective way to stop a variety of exploits that target the widespread Microsoft vulnerability.

Bulletin Revised

In response to the issues raised by Maiffret, Cooper, and others, Microsoft on Tuesday updated the relevant Security Bulletin to say that disabling DCOM only works on Windows 2000 systems running Service Pack 3 or later.

While expressing regret about the confusion, Microsoft's Toulouse says the company does not support Windows 2000 systems running anything less than Service Pack 3, and that its patches are only guaranteed to work on versions of Windows that are supported.

Microsoft's policy is to only support operating systems running one of the two latest service packs, according to Toulouse.

However, responding to concerns about the Blaster worm, Microsoft on Tuesday extended support for the RPC vulnerability patch to Windows 2000 SP2 systems and updated its security bulletin.

Microsoft's existing policy regarding which service packs it will patch angers security professionals like Cooper.

"I find it untrustworthy that Microsoft wouldn't consider during an event like this supporting a widely deployed platform such as Windows 2000 with Service Pack 2," he said, speaking on Tuesday before he knew that Microsoft had updated its bulletin.

Reacting to the change on the NTBugtraq discussion list late Tuesday after Microsoft updated the security bulletin, Cooper expressed frustration with the company's slow response, observing that the RPC patch was designed to work for Windows 2000 SP2 from the very start.

"It's taken them 27 days to officially say it will work on a platform they designed it for," he said.

Complaints Noted

Toulouse on Wednesday acknowledged the friction with some Windows users and said the company is evaluating its procedures for supporting older versions of its operating systems in the event of widespread vulnerabilities and virus outbreaks.

"We're going to take a good look at how we're communicating with our customers and what we're doing," he says. "What this shows us, in general, is that we have opportunity here to do more to help customers protect their information."

Future changes to Microsoft policy are possible, Toulouse said.

"We've done a lot right with this [vulnerability alert] but we're still learning. There are always more things we can do," he says.

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