Waiting for the other shoe to drop: That's what I've been doing since last Thursday when Microsoft released the out-of-cycle MS08-067 bulletin and accompanying patches. It's more than a little nerve-wracking knowing that there is this vulnerability in machines within networks that you're responsible for but know that they can't all be patched right now due to various reasons and there is active exploitation of this vulnerability going on elsewhere in the world. What's most disturbing is that this is a vulnerability that allows a successful attacker to gain remote system-level privileges on a vulnerable Windows system.What do you do? With regards to the clients I don't manage directly but provide consultation to the sysadmins, I've sent notifications letting them know about the vulnerability, the impact of successful exploitation, and the likelihood of them having machines exploited by it based on what I know of their network design and protection mechanisms. At that point, that's all I could do to directly influence they get patched.

From a network security perspective, since I manage the network router, firewalls, and IDS at some of my clients, I made sure that the firewalls rules were still configured the way I had set them up initially, default deny--basically, everything is blocked except for a few things required for e-mail and web browsing. The only way for internal machines to be exploited is if an internal machine is infected with malware through a client-side exploit that then downloads a malicious payload to exploit internal machines or an infected laptop is plugged in that starts scanning and exploiting.

On Thursday night, SecureWorks provided over 30 MS08-067 related signatures for the Snort IDS that were incorporated into the Emerging Threats rulesets. I'm now running those along with several others related to MS08-067-specific malware and IP addresses associated with malicious payloads downloaded by the malware.

At this point, I'm doing what many of you out there are doing; sitting and watching logs, monitoring for anything that might be an outbreak of a new MS08-067 worm or similar. This is one of those vulnerabilities that just screams "worm," and I think it was Microsoft who said first that it was "wormable." The question on everyone's mind right now (at least those with unpatched machines), is when will my network full of "worm food" get eaten?

John H. Sawyer is a Senior Security Engineer on the IT Security Team at the University of Florida. The views and opinions expressed in this blog are his own and do not represent the views and opinions of the UF IT Security Team or the University of Florida. When John's not fighting flaming, malware-infested machines or performing autopsies on blitzed boxes, he can usually be found hanging with his family, bouncing a baby on one knee and balancing a laptop on the other. Special to Dark Reading.