Security researchers at G Data have discovered pre-installed malware on over two-dozen models of Android smartphones shipping from Asia.

The phones infected with malware out-of-the-box include some well-known brands such as Lenovo, Huawei, and Xiaomi.

In total, Germany-based G Data says it discovered over 26 models infected with malware capable of stealing personal information, recording calls, transmitting location data and serving up ads and spyware without the user’s knowledge or consent. Most of the models are sold within the Asian region.

In each case, the smartphone manufactures themselves do not appear to be involved in pre-installing the malware on brand new Android phones, says Andy Hayter, security evangelist for G Data.

Instead, the tampering appears to be happening somewhere in the distribution chain, after the manufacturer ships the devices but before the devices get into the hands of consumers. “Someone is unlocking these phones, installing the malware on them and locking them up again,” Hayter says. He added that the level of sophistication required to pull off the operation without being noticed would be fairly significant. “It takes a certain amount of risk to do this,” he says.

In most of the cases that G Data reviewed, the malware is typically hidden in a legitimate looking application like Facebook, Hayter said. The malware is concealed inside the usual functions of the legitimate application and few notice it because a majority of the malicious processes run in the background, he said.

The add-on functions that are being secretly added to Facebook and other pre-installed apps are designed to perform a wide range of malicious actions. They include surreptitiously accessing the Internet, reading and sending SMS messages, accessing contact lists, altering call data and listening to and recording phone conversations.

G Data made the news last year when its researchers discovered the Star N9500 Galaxy S4 clone, sold through online stories like Amazon and eBay, to be pre-installed extensively with spyware tools. This year’s research shows the problem has gotten significantly worse, Hayter said.

Based on the research so far, it is hard to determine if the pre-installed malware is the handiwork of one group or multiple groups. But it is very likely that multiple groups are involved considering the sheer geographic spread of the problem and the number of impacted brands.

“From the variety of phones we see, the idea [to pre-install malware] is spreading,” Hayter said. Besides Lenovo, Huawei and Xiaomi, some of the other, lesser-known, Android brands impacted by the problem include several models of Alps, the ConCorde SmartPhone6500, DJC Touchtalk, ITouch and Sesonn.

G Data’s findings on pre-installed malware on Android smartphones shipping from Asia are part of a broader report on the state of Android malware for the second quarter of 2015.

As with previous quarters, security researchers at G Data discovered a sharp increase in the number of Android malware samples in the wild.

According to G Data, its researchers analyzed some 6,100 new malware samples every day during the second quarter compared to the 4,900 malware apps per day analyzed in the previous quarter. In total, G Data researchers discovered over one million new Android malware strains in the first six months of the year, a new record for Android malware, according to Hayter.

In addition to the surging numbers, the researchers discovered that Android malware is also becoming increasingly sophisticated.

Fortunately for Android users, the malware presents a threat mostly to people who purchase their devices through less-than-reliable online sources, or those who install apps outside of Google’s Play store and other legitimate application stores. Despite the surging malware count, users who buy through legitimate sources and stick with official application stores for the most part remain relatively protected.