Security researchers from Malwarebytes found pre-installed malware on UMX U683CL handsets. The phones are made under the Lifeline program to low-income consumers for Affordable Communications.

Multiple users reported to Malwarebytes that HiddenAds suddenly get installed on their UMX mobile phone, so the company purchased a UMX U683CL for further analysis.

Malware Comes Pre-Installed

The UMX U683CL phones offered by Assurance Wireless and it cost only $35 under the government-funded program.

Once the user logs into the device a questionable app named Wireless Update, starts auto-installing apps without user consent. It doesn’t notify users or request any permission to install apps, it just installs the apps on its own.

A malicious app detected as Android/PUP.Riskware.Autoins.Fota.fbcvd get’s installed during the update process. The Agent is heavily obfuscated and it is a vital part of the system. It is a variant of Adups malware.

It is a malicious firmware that comes preinstalled on the devices and it has system-level rights, Malwarebytes able to confirm the firmware presence on the phones.

“It’s with great frustration that I must write about another unremovable pre-installed app found on the UMX U683CL phone: the mobile device’s own Settings app functions as a heavily-obfuscated malware we detect as Android/Trojan.Dropper.Agent.UMX.”

“The more discernible variant of this malware uses Chinese characters for variable names. Therefore, we can assume the origin of this malware is China.”

The Trojan agent downloads another piece of the malware known as HiddenAds. The malware strains display aggressive ads and it is hard for an end-user to find which app displaying the ads.

Malwarebytes informed Assurance Wireless about their findings of the devices with pre-installed, but Assurance Wireless didn’t respond.

To note the UMX mobile device is made by a Chinese company, it’s unclear who installed the malware as several companies involved in the device supply chain between device manufacturer to the buyer.

There is no current solution, uninstalling the wireless Update may lead to missing out critical OS updates.