Android Malware 'Triada' Most Active on Telco Networks

New research into the impact of Triada, a sophisticated remote access Trojan that was recently found pre-installed on numerous Android devices, has shown that more than 15% of telecom companies globally have infected devices running on their network.

Security ratings firm BitSight, which has been tracking the malware since May, recently gathered telemetry from command-and-control domains that Triada-infected devices have been communicating with.

BitSight also looked for telemetry related to PrizeRAT - a remote access Trojan that like Triada was found pre-installed on some low-cost Android devices last year - and for data pertaining to Ztorg, a lightweight Trojan that in the past has been associated with Triada.

The research showed that all three malware strains impact networks in the telecommunications sector far more so than any other industry. BitSight's data suggested that more than 25% of telecommunications networks have PrizeRAT-infected devices running on them, more than 20% have Ztorg and 15.5% have Android systems with Triada installed. In many cases, the devices were infected via shifty applications downloaded from unapproved third-party Android app stores.

BitSight found devices infected with at least one of the three mobile malware strains are present on other networks as well though on a much smaller scale.

More than 5% of education networks, for instance, contain Android devices that are infected with PrizeRAT, and about 0.6% of them have Triada-infected Android phones and tablets. BitSight found that Ztorg had a stronger presence on networks belonging to companies in the utilities, government and retail sectors — with 1.27%, 1.4%, and 0.79%, of organizations impacted, respectively.

The reason for the relatively heavy presence of infected systems on telecom and education sector networks is likely because many of the devices belong to consumers and students. "The telecommunications and education industry sectors often do not enforce security controls on devices communicating through their networks since they primarily offer transit services to their customers, or students in the case of the latter," says Dan Dahlberg, a security researcher at BitSight.

Devices infected with Triada and PrizeRAT include those running Android 9.0 and other recent versions of the operating system Ztorg has generally been infected devices running Android 5.1.1 and older according to the company.

Tiago Pereira, a security researcher at BitSight, says these malware strains pose a risk to organizations that are storing and processing data on mobile devices. "These malware families place the data on those devices at risk and may give the same level of access as the device owner to corporate assets," he says. "Organizations should consider this as a real attack vector and deploy countermeasures to it."

A Sophisticated Threat

Google in May disclosed that it had learned of Triada being pre-installed on some Android devices via a system image backdoor. According to Goolge, a company named Yehuo or Blazefire likely supplied the infected system image to some Android equipment manufacturers during the production process in a supply chain attack.

Researchers have known about Triada for sometime. In a July 2016 blog, Kaspersky Lab described the mobile malware as one of the most sophisticated of its kind the company had encountered. Triada works by modifying Zygote, a core process in the Android OS so it becomes part of every application on the infected device, the company had noted. At the time, Symantec said Triada had the potential to impact a high number of Android devices.

As far back as July 2017, antivirus firm Dr. Web had warned about Triada being built into the firmware of several Android devices. Dr. Web, Google, and others have described Triada as capable of penetrating processes on all running Android applications and of downloading and running additional malicious payloads.

Initially at least, the malware's purpose was to install apps for displaying ads on an infected device for ad fraud purposes. But Triada is modular and can be easily repurposed for other malicious purposes, the vendors have warned. The only way to get rid of it from systems on which it is pre-installed is to upgrade the firmware.

Ztorg, meanwhile, is a lightweight Trojan that attackers have been using to download Triada on Android devices. The relatively high presence of Ztrog on utility, government, and retail networks could spell potential trouble for organizations in those sectors.

According to BitSight, most organizations that have been impacted by Triada so far have a security rating of 400 or lower, meaning their security practices lag well behind industry standards. Metrics that are used to calculate an organization's risk scores include the currency of operating systems and browsers, and the number of services that are exposed externally on corporate networks.

"Previous studies we've done also demonstrated that organizations with a rating of 400 or lower were five times more likely to experience a publicly disclosed data breach than companies with a 700 or higher," Dahlberg says.

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