Here's the scoop on the Windows animated cursor bug

Microsoft is promising an early patch for the ANI vulnerability

When a major vulnerability affecting every flavor of Windows -- including Vista -- breaks, it only seems like chaos ensues. Okay, so it is chaos. Witness the so-far short-lived flaw in Windows' animated cursors (ANI), which picked up enough steam over the weekend to power a turbine or two. IT staff, small business users and consumers have been trying to figure out which way is up, and whether this is a Big Deal or just another security industry siren blaring in the background. This FAQ on the flaw, explains what it is, which machines are at risk and what you can do to protect yourself.

What's the problem, anyway? A critical flaw in User32.dll, specifically in the code of that Windows .dll that loads animated cursor (.ani) files, which are used to trick out the cursor, changing it from a simple pointer to a short animation. Microsoft, for example, sometimes includes animated cursors in its optional visual theme downloads. Exploits targeting the bug can use ANI files to run malicious code on a victimized PC, infecting it with spyware, stealing identity information or adding it to a botnet of hijacked systems.

When did this pop up? Microsoft says it was first notified in late December 2006 by researchers at Determina, but others -- including Marc Maiffret of eEye Digital Security -- point out that the vulnerability is very similar to one patched in January 2005 that also affected cursor files. It wasn't until last week -- March 28, to be exact -- that attacks using the exploit were spotted in the wild (by McAfee) and reported to Microsoft's Security Response Center (MSRC).

What versions of Windows are vulnerable? This is the cropper, isn't it? One of the things that makes the ANI bug so dangerous is that it affects every still-supported edition of Windows, including Windows 2000 SP4, XP SP2, Server 2003 (up to SP2), and even Vista. Both 32- and 64-bit versions are at risk.

What about Linux or Mac systems? Are they at risk, too? Hahahahahaha. Sorry. Nope.

Are hackers using the vulnerability? Funny. China's Internet Security Response Team (CISRT) warned over the weekend that a worm exploiting ANI was in the wild. Symantec tagged the worm as Fubalca, while other security companies -- no surprise here -- applied different monikers. McAfee, for instance, calls it Fujacks.aa, while Computer Associates labeled it MSA-935423!exploit. Nothing like consistency. Other reports have cited one or more spam runs that include links to malicious sites hosting an ANI exploit, while the newest information from Websense Inc. is that there are at minimum 150 Web sites circulating the attack. So the short answer, unfortunately, is yes.

Join the newsletter!

Or

Sign up to gain exclusive access to email subscriptions, event invitations, competitions, giveaways, and much more.

Membership is free, and your security and privacy remain protected. View our privacy policy before signing up.

Error: Please check your email address.
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.
Gregg Keizer

Gregg Keizer

Computerworld
Show Comments

Brand Post

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Tom Pope

Dynabook Portégé X30L-G

Ultimately this laptop has achieved everything I would hope for in a laptop for work, while fitting that into a form factor and weight that is remarkable.

Tom Sellers

MSI P65

This smart laptop was enjoyable to use and great to work on – creating content was super simple.

Lolita Wang

MSI GT76

It really doesn’t get more “gaming laptop” than this.

Jack Jeffries

MSI GS75

As the Maserati or BMW of laptops, it would fit perfectly in the hands of a professional needing firepower under the hood, sophistication and class on the surface, and gaming prowess (sports mode if you will) in between.

Taylor Carr

MSI PS63

The MSI PS63 is an amazing laptop and I would definitely consider buying one in the future.

Christopher Low

Brother RJ-4230B

This small mobile printer is exactly what I need for invoicing and other jobs such as sending fellow tradesman details or step-by-step instructions that I can easily print off from my phone or the Web.

Featured Content

Product Launch Showcase

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?