ANTenna Blog -- Security

The latest ActiveX vulnerability could create big problems in the form of big opportunities for hackers. How big? The Conficker worm exploited a vulnerability that was long-patched, taking advantage of unpatched computers. The new vulnerability hasn't been patched yet. You do the math.

The Video ActiveX Control vulnerability, acknowledged by Microsoft this week, but evidently known of for as much as a year and a half, is exploited via versions of Internet Explorer, enabling the execution of illicit programs on Windows XP and Windows Server 2003 systems.

That the vulnerability is browser-exploitable is the bad news: attacks can be surfed in to vulnerable systems by innocent users. The good news is that it's exploitable only through IE6 and IE7; users who've upgraded to IE8 are immune, as are Vista and Windows7 users.

But it's the fact that this is an unpatched vulnerability the gives the most pause and raises the largest alarms.

Conficker made its way into as many as 12 million machines despite a long-available patch for the vulnerability it exploited. The problem -- and the opportunity for the crooks -- was the lax (to say the least) approach to patching on those machines.

The new exploit is unpatched as yet, a fact that may more than outweigh the fact that it affects relatively elderly code.

Whether or not this new ActiveX vulnerability opens enough doors to permit entry of a bigger, badder Conficker isn't clear.

Microsoft promises a patch soon, but until then a workaround is available from Microsoft here. The workaround disables the Video ActiveX control in question.

Don't put this one off -- if you or any of your employees are running Windows XP or Windows Server 2003, implement the workaround now.

Microsoft has labeled this vulnerability critical, which of course it is. And, of course, which it has been for as long as Microsoft has known about and not fixed it.