While it may be hard to fathom, considering the extraordinary amount of coverage and speculation that swirled about Dan Kaminsky's DNS vulnerability announcement, Kaminsky today said that the flaw is much more serious than previously speculated.

As expected, Kaminsky, who is director of pen testing for security firm IOActive, today spoke to a room jam-packed with Black Hat goers. He explained that while most focused on cache poisoning attacks, the DNS vulnerability also could be used to attack VoIP, IPSec VPNs, SSL certs, automatic software update systems, and, quite surprisingly to me, anti-spam filters. Oh, yeah: this isn't a complete list, more like a starting point for the type of damage this vulnerability, if exploited, could usher in.

I found this Kaminsky quote to be quite cheerful: "There are many, many variants of this attack, and there are a ton of different paths that lead to doom." And if you thought that by moving your DNS behind your firewall brought you any safety, think again. His presentation pretty much proved that those firewall policies are of little use, and the flaw can be exploited through links, images, and advertisements in Web browsers, e-mail servers, and code inserted within documents that "call home."

The good news is that 120 million broadband consumers are now protected from the DNS vulnerability through their service providers that have applied the patch. "There has been a remarkable amount of uptake on this patch," Kaminsky said. "Home users at this point more likely than not are behind a protected environment, and they're actually probably going to be more unsafe at work."

While most home users are now protected because their ISP has probably deployed patches that fix the flaw, most of the Fortune 500, about 70%, he estimates, have applied the patch, with the remaining 30% either unpatched, or have patched but still have NAT woes.

So a great swathe of small and midsized business are probably still at significant risk.