On the second Tuesday of each month, Microsoft releases its security bulletins and vulnerability patches for the month. Some months may have no new security bulletins or just a couple, but the month of August is not one of those.
What is different about this month is that one of them, Security Bulletin MS06-040, affects the Server Service and is capable of being exploited easily by a fast-spreading worm. Arguably, MS06-040 should have received an even higher designation, such as "Urgently Critical."
The threat of a crippling worm attack was serious enough that even the Department of Homeland Security (DHS) took notice. The DHS issued a warning of its own recommending that all users expedite the application of the MS06-040 patch. As of Sunday, Aug. 13, there were already worm variants spreading in the wild that use an exploit of the MS06-040 vulnerability to propagate.
While users and companies scramble to apply the patch, there are some other mitigation steps that you can take as well, such as:
- eEye Digital Security offers a free tool to scan for and identify vulnerable systems on your network (the eEye Web site may be difficult to get to due to the volume of users trying to download this tool).
- Block ports 139 and 445 at the firewall to ensure that the worm is not able to spread to your internal network from the Internet.
While there isn't as much hype or urgency to the other patches, critical or otherwise, the majority of the critical patches, if exploited, could result in attackers being able to execute malicious code of their choice on the vulnerable machine. You may want to be more thorough in evaluating or testing these patches before rushing to deploy them, but you should still have a sense of urgency and work to expedite patch deployment as much as possible.
One patch has caused many companies problems. The Cumulative Security Update for Internet Explorer, related to Security Bulletin MS06-042, has been reported to cause the Internet Explorer Web browser to crash on Windows 2000 SP4 and Windows XP SP1 systems. (Editor's note: Microsoft has issued a fix for this glitch.) For more information about known issues with this patch, you can refer to Microsoft Knowledge Base Article 918899.
About the author: Tony Bradley is a consultant and writer with a focus on network security, antivirus and incident response. He is recognized by Microsoft as an MVP in Windows Security, and he is the About.com Guide for Internet / Network Security, providing a broad range of information security tips, advice, reviews and information. Tony is co-author of Hacker's Challenge 3 and author of the upcoming Essential Computer Security. He also contributes frequently to other industry publications. For a complete list of his freelance contributions you can visit S3KUR3.com.