With the spread of the dangerous new W32/Blaster Windows worm slowing, attention is shifting to Microsoft Corp.'s efforts to help its customers patch vulnerable systems, with some accusing the company of providing inadequate protection and unreliable information about protecting their computers.
The new worm, W32.Blaster, first appeared on the Internet on Monday and quickly spread worldwide, infecting hundreds of thousands of computers and causing disruptions on corporate and university networks, as well as on home computers.
Blaster targets a Windows component for handling RPC (Remote Procedure Call) protocol traffic called the Distributed Component Object Model (DCOM) 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 at Symantec Corp.
A new variant of Blaster also appeared Wednesday and seemed to be spreading, according to antivirus companies.
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 were covered by the patch have come under increasing scrutiny as the Blaster worm has spread.
After reports surfaced on the Internet, the Redmond, Washington company 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," said Stephen Toulouse, security program manager at Microsoft.
The workaround required Windows users or administrators to change a Windows configuration setting to disable DCOM.
However, changing that setting had 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 Inc.
Microsoft also failed to explain that Windows systems needed to be restarted following the configuration change to be protected, he said.
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 have still been vulnerable, Maiffret said.
So far there haven't been any reports of infections due to the confusion over disabling DCOM, according to Russ Cooper, Surgeon General of TruSecure Corp. and moderator of the popular discussion list NTBugtraq.
In addition, the application of certain patches for the Windows 2000 operating system did allow users to properly disable DCOM, Cooper said.
Cooper recommended that affected users disable DCOM because it was the most effective way to stop a variety of exploits targeting the widespread Microsoft vulnerability.
In response to the issues raised by Maiffret, Cooper and others, Microsoft on Tuesday updated its Security Bulletin regarding the DCOM vulnerability to say that disabling DCOM only works on Windows 2000 systems running Service Pack 3 or later. (See http://www.microsoft.com/technet/treeview/?url=/technet/security/bulletin/MS03-026.asp.)
While expressing regret about the confusion, Microsoft's Toulouse said that 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.
That policy angers security professionals like Cooper, however.
"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.
Toulouse 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. What this shows us, in general, is that we have opportunity here to do more to help customers protect their information," he said.
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 said.