Unpatched Java vulnerability exploited to infect Macs with Flashback malware

The Flashback.K variant is distributed via exploits for a known Java vulnerability that Apple has yet to patch

A Java vulnerability that hasn't yet been patched by Apple is being exploited by cybercriminals to infect Mac computers with a new variant of the Flashback malware, according to security researchers from antivirus firm F-Secure.

Flashback is a computer Trojan horse for Mac OS that first appeared in September 2011. The first variant was distributed as a fake Flash Player installer, but the malware has been changed significantly since then, both in terms of functionality and distribution methods.

Back in February, several antivirus companies reported that a new Flashback version was being distributed through Java exploits, which meant that the infection process no longer required user interaction.

The Java vulnerabilities targeted by the February exploits dated back to 2009 and 2011, so users with up-to-date Java installations were protected.

However, that's no longer the case with the latest variant of the malware, Flashback.K, which is being distributed by exploiting an unpatched Java vulnerability, security researchers from F-Secure said in a blog post Monday.

Oracle released a fix for the targeted vulnerability, which is identified as CVE-2012-0507, back in February and it was included in an update for the Windows version of Java.

However, since Apple distributes a self-compiled version of Java for Macs, it ports Oracle's patches to it according to its own schedule, which can be months behind the one for Java on Windows.

Security experts have long warned that this delay in delivering Java patches on Mac OS could be used by malware writers to their advantage, and the new Flashback.K malware confirms that they were right.

After being dropped and executed on the system via the CVE-2012-0507 exploit, the new Trojan horse prompts a dialog window that asks the user for their administrative password.

Regardless of whether the user inputs the password or not, the malware still infects the system, F-Secure said in its description of the malware. The Trojan's purpose is to inject itself into the Safari process and modify the contents of certain Web pages.

There are rumors that a new exploit for a different unpatched Java vulnerability is currently being sold on the underground market and could be used to target Mac users in a similar way in the future, the F-Secure researchers said.

"If you haven't already disabled your Java client, please do so before this thing really become an outbreak," they said. The antivirus company provides instructions on how to do this.

Apple stopped including Java by default in Mac OS X starting with version 10.7 (Lion). However, if Lion users encounter a Web page that requires Java, they are prompted to download and install the runtime and might later forget that they have it on their computers.

Join the Good Gear Guide newsletter!

Error: Please check your email address.

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Lucian Constantin

IDG News Service
Show Comments

Essentials

Microsoft L5V-00027 Sculpt Ergonomic Keyboard Desktop

Learn more >

Lexar® JumpDrive® S57 USB 3.0 flash drive

Learn more >

Mobile

Lexar® JumpDrive® S45 USB 3.0 flash drive 

Learn more >

Exec

Lexar® Professional 1800x microSDHC™/microSDXC™ UHS-II cards 

Learn more >

HD Pan/Tilt Wi-Fi Camera with Night Vision NC450

Learn more >

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

Learn more >

Budget

Back To Business Guide

Click for more ›

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

Azadeh Williams

HP OfficeJet Pro 8730

A smarter way to print for busy small business owners, combining speedy printing with scanning and copying, making it easier to produce high quality documents and images at a touch of a button.

Andrew Grant

HP OfficeJet Pro 8730

I've had a multifunction printer in the office going on 10 years now. It was a neat bit of kit back in the day -- print, copy, scan, fax -- when printing over WiFi felt a bit like magic. It’s seen better days though and an upgrade’s well overdue. This HP OfficeJet Pro 8730 looks like it ticks all the same boxes: print, copy, scan, and fax. (Really? Does anyone fax anything any more? I guess it's good to know the facility’s there, just in case.) Printing over WiFi is more-or- less standard these days.

Ed Dawson

HP OfficeJet Pro 8730

As a freelance writer who is always on the go, I like my technology to be both efficient and effective so I can do my job well. The HP OfficeJet Pro 8730 Inkjet Printer ticks all the boxes in terms of form factor, performance and user interface.

Michael Hargreaves

Windows 10 for Business / Dell XPS 13

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Aysha Strobbe

Windows 10 / HP Spectre x360

Ultimately, I think the Windows 10 environment is excellent for me as it caters for so many different uses. The inclusion of the Xbox app is also great for when you need some downtime too!

Mark Escubio

Windows 10 / Lenovo Yoga 910

For me, the Xbox Play Anywhere is a great new feature as it allows you to play your current Xbox games with higher resolutions and better graphics without forking out extra cash for another copy. Although available titles are still scarce, but I’m sure it will grow in time.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?