A few updates ago, Skype added advertisements to its world-famous messaging software. Unfortunately, users are reporting that some of those advertisements are malicious and trying to trick users into downloading spyware.
Skype’s advertisements appear at the top of the screen in the form of a banner as well as on the main “Home” page in the form of a square box advertisement. They’re relatively large, and users have complained about their intrusiveness ever since they were introduced.
But recently, users have complained about more than just the intrusiveness of the advertisements: they’ve complained that advertisements are wrecking their computers.

At least one advertisement tries to install spyware

Starting on Monday, users of the Skype community forum started complaining that they were seeing a banner advertisement on Skype. That banner advertisement, when clicked on, led to a dodgy website that attempted to install software disguised as an Adobe or Java update.

As you may know, this is a common tactic used by spyware and malware developers on the internet. You usually see these types of advertisements on seedy websites. Where you don’t expect to see them, however, is at the top of your Skype client.

Users are being tricked into downloading malware

The advertisement at the top of Skype claims that users need to update their Adobe or Java. Since Skype is a Microsoft program and a legitimate, well-known piece of software, users think that Windows is delivering a legitimate software update warning.

That’s why even experienced PC users are falling for this trick.
Unfortunately, if you do fall for the trick, you’re not downloading an Adobe or Java update: you’re downloading a dangerous piece of malware. It’s unknown what exactly that malware does to your system, but it’s unlikely that it does anything good.

How Skype is responding

Skype is trying to get to the bottom of the issue. In the Skype community forum thread, a Skype technician asked one of the affected users to run a Fiddler trace to identify where the web traffic was going, which would help Skype identify the issue further.

At this point, Skype has not responded to this issue nor has it confirmed that the malicious advertisement has been removed from the system.
Ultimately, Skype is a free service, and Microsoft is a business, not a charity. If you want to keep using Skype for free, you’re going to have to get used to the advertisements: just try to avoid clicking on those advertisements no matter how tempting they may seem.