Avast, a prominent security agency, reported that its security threat lab found that many of its Android phones, such as ZTE, Myphone, and other manufacturers, were preloaded with malicious adware. The malware is named "Cosiloon", which overrides the display of an ad at the top of the page when the user uses the browser to surf the internet.
Avast says the malware has been quietly in existence for at least three years and is preinstalled on the handset's firmware level, which is almost impossible for ordinary users to completely erase.
Avast observes that because these phones have not been certified by Google, has led to thousands of of users, especially in recent months, has found about 18,000 mobile phones in the presence of this malware, and in more than 100 countries and regions, the hardest-hit areas are Russia, Italy, Germany, Britain and the United States.
Avast has reported this to Google, which is taking steps to remove the malicious application variants on some devices through in-house technology. But because of the combination of malware and handset firmware, Google is not a good way to contact the firmware developer, urging it to resolve the issue.
Avast: ZTE phones pre-installed malware embedded in firmware bottom