A remote-code exploit that could spread rapidly like the 2003 MSBlaster worm is putting all versions of Windows at risk.
I recommend that you immediately install a patch that Microsoft has just issued to protect your system from a vulnerability in the Server service.
MS08-067 (958644)
Rare out-of-cycle patch emphasizes the risk
With little warning, Microsoft released yesterday an unscheduled or "out-of-cycle" patch for a highly critical vulnerability that affects all versions of Windows. Security bulletin MS08-067 (patch 958644) was posted to warn of a remote-code attack that could spread wildly across the Internet.
Microsoft says it found evidence two weeks ago of an RPC (remote procedure call) attack that can potentially infect Windows machines across the Net with no user action required.
Windows Server 2003, 2000, and XP (even with Service Pack 2 or 3 installed) are particularly vulnerable. Vista and Server 2008 gain some protection via User Account Control, data-execution protection, and other safeguards, as explained in an article by Dan Goodin in the Register.
While firewalls are a first line of defense against this attack, don't think you're secure just because you have a firewall. Malware and viruses use many different techniques to wiggle their way into our systems.
For example, my office's networks are protected by firewalls on the outside, but inside the network, PCs have file and printer sharing enabled. If a worm got loose inside the office network (and the patch hadn't been installed), the attack would spread like wildfire.
Many antivirus vendors have already issued definition updates that protect against this attack. Your antivirus program, however, may not protect you completely even if your AV definitions are up-to-date. Early reports indicate that there are already nine different strains of viruses trying to take advantage of this vulnerability. We can expect more to come, so even the best AV application may not be able to update fast enough.
I've tested this patch and have had no problems applying it. I strongly urge you to download and install this patch manually. Restart your PC before installing any patch to verify that your machine is bootable. Then be sure to reboot again after installing the patch, so the patched binaries completely replace the vulnerable components.
Microsoft has posted several versions of the patch that apply to different operating systems:
Windows 2000 with Service Pack 4
patch download
Windows XP with Service Pack 2 or 3
patch download
Windows XP 64-bit Edition
patch download
Windows Server 2003 with Service Pack 1 or 2
patch download
Windows Server 2003 64-bit Edition
patch download
Windows Vista 32-bit Edition with or without Service Pack 1
patch download
Windows Vista 64-bit Edition with or without Service Pack 1
patch download
Windows Server 2008 32-bit Edition
patch download
Windows Server 2008 64-bit Edition
patch download
More information: Please read security bulletin
MS08-067. For an excellent technical explanation of the vulnerability and possible mitigations, read TechNet's Oct. 23 description. (TechNet incorrectly refers to MS08-067 as "out-of-band," but the patch is simply out-of-cycle, because it wasn't released on Microsoft's usual Patch Tuesday monthly cycle.)
Thanks to Susan Bradley of Windows Secrets for the article.
