On July 4, researchers from mobile protection firm TrustGo detected a new piece of malware targeting Android. Unlike other Android attacks however, this one gained a large install-base rather quickly – infecting 100,000 devices in less than a week.
The malware, named "Trojan!MMarketPay.A@Android" by TrustGo, is targeting customers of China Mobile, China’s largest carrier with some 6 million subscribers. TrustGo has found examples of the malware in nine different third-party application stores, which seem to specialize in the cloning of legitimate applications.
What is interesting about TrustGo’s discovery is the malware’s main function. Once installed on a victim’s device, it can place orders automatically on behalf of users. The malware is able to initiate the purchase of applications and streaming video by capturing the verification codes delivered by SMS. Once a China Mobile user authenticates with the SMS code, additional purchases are simply approved and added to their bill.
Such a design is sure to lead to enormous phone bills down the line – and presumably a huge commission for someone. If the purchases trigger additional security, such as CAPTCHA images, those are sent to a remote location for examination.
“The ease and speed that malicious apps can be developed and distributed to unsuspecting users is one of the fastest growing security concerns. Anyone with a smartphone or mobile device is a potential target,” said Xuyang Li, CEO of TrustGo.
“Malicious mobile applications that covertly charge users for premium services, such as the new applications that are infecting thousands of Android devices in China, are becoming an increasing problem," said Neil Roiter, Director of Research at Corero Network Security. "It is essential that people download applications only from authorized Android application stores and do some research online before they download anything. It's also a good idea to check your phone bill for unusual charges to ensure that that you are not paying for services that you didn't subscribe to.”