According to company's global security report, most of the third-party apps are malware-affected.
"The number of Android viruses, especially Root Trojans, rose sharply with a growth rate of 22 percent infecting a total of 11,170,960 devices in India in 2015," the report said.
The report found that China, India and Indonesia were the three most severely afflicted countries and detailed the growth of viruses, phishing sites, malwares, infected devices across major markets and data leakages.
The report, which focused on virus infections in Android devices all over the world, said the number of Android viruses exceeded 9.5 million in 2015, which is larger than twice the total number in the past three years. The number stood at 2.8 million in 2014.
"Root Trojans can take complete control of the device and are hard to remove. From the Stagefright vulnerability, which affected 95 percent Android devices to the wormhole compromising millions, it seemed like Android vulnerabilities would never end," the report said.
Stagefright is the collective name for a group of software bugs that affect Android operating system, allowing an attacker to perform arbitrary operations on the victim device through remote code execution.
Apart from large Android user bases, another reason of these countries becoming the worst-hit ones is that third-party app markets are prevailing in these areas, and most of these third-party app markets have been contaminated by malwares due to the weak monitoring.
A Trojan Horse or Trojan is a type of malware that is often disguised as legitimate software. Trojans can be employed by cyber thieves and hackers trying to gain access to users' systems.
The company's annual security report is cumulative data based on 567 million global monthly active users and an overall install base of almost two billion users using Cheetah Mobile's utility applications on their devices.