Exploit-powered Android Trojan uses update attack

A new DroidKungFu variant poses as a legit application update

A new variant of the DroidKungFu Android Trojan is posing as a legitimate application update in order to infect handsets, according to security researchers from Finnish antivirus vendor F-Secure.

Distributing Android malware as updates is a relatively new tactic that was first seen in July. The primary method of infecting handsets continues to be the bundling of Trojans with legitimate applications; however, the resulting apps are easy to spot because of the extensive permissions they request at installation time.

According to security researchers, the new update-based attacks can have a higher success rate than "Trojanizing" apps, because users don't tend to question the legitimacy of updates for already-installed software.

Furthermore, when used by threats like DroidKungFu, update attacks can be hard to detect without specialized antimalware tools. That's because these Trojans use Android exploits to gain root access and then deploy their malicious components unhindered.

The new DroidKungFu variant is distributed with the help of a non-malicious application currently available from third-party app stores in China. However, the threat is global because apps infected with earlier versions of the Trojan have been detected on the official Android Market in the past.

"Once installed, the application would inform the user that an update is available; when the user installs this update, the updated application would then contain extra functionalities, similar to that found in DroidKungFu malware," the F-Secure researchers warn.

The update only asks for access to SMS/MMS messages and location, but also contains a root exploit for Android 2.2 (Froyo) that unlocks all system files and functions. Even though this particular DroidKungFu variant doesn't target devices running Android 2.3 (Gingerbread), there are other Trojans that infect this version of the operating system and could adopt the same attack technique in the future.

In addition, there is reason to believe that the malware's authors are also testing other infection methodologies. Last week, security researchers from mobile antivirus vendor Lookout detected another DroidKungFu variant that doesn't use root exploits at all.

Instead, the new Trojan, which Lookout calls LeNa, uses social engineering to trick users into giving the installer super-user access on devices where users have knowingly executed a root exploit. Once deployed, the malware attaches itself to a native system process.

"This is the first time an Android Trojan has relied fully on a native ELF binary as opposed to a typical VM-based Android application," the researchers explained. The malware is distributed by rogue VPN (virtual-private-network) applications, some of which were found on the official Android Market.

Join the Good Gear Guide newsletter!

Error: Please check your email address.

Tags securityAccess control and authenticationDesktop securityf-secureExploits / vulnerabilitiesdata protectionmalware

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

Lexar® JumpDrive® S57 USB 3.0 flash drive

Learn more >

Microsoft L5V-00027 Sculpt Ergonomic Keyboard Desktop

Learn more >

Mobile

Lexar® JumpDrive® S45 USB 3.0 flash drive 

Learn more >

Exec

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

Learn more >

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

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

Learn more >

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

Learn more >

Budget

Back To Business Guide

Click for more ›

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

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.

Kathy Cassidy

STYLISTIC Q702

First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni

STYLISTIC Q572

For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?