Jakarta. Cybersecurity firm CSIS Security Group has warned Android users of malware dubbed Joker hidden inside several applications on Google Play.

About 1.25 billion Android users are at risk from an "update setting" in apps that have all been found to carry the trojan, and which had been downloaded by nearly half a million users.

"So far, we have detected it in 24 apps with over 472,000 installs in total," Aleksejs Kuprins, a security researcher at the CSIS Security Group, said in his blog.

He said the malware silently simulates interaction with advertisement websites and steal users' text messages, contact lists and device information. The app also subscribes users to premium services in the background, which could have financial implications for users.

Kuprins said the malware was targeting users in 37 countries, including Indonesia. Google Play has removed all the affected apps, but the trojan may still be around, as it has been installed on so many phones, where it has access to contact lists.

If you have any of the affected apps, listed below, on your phone, remove them immediately. If you have used any of the apps, check your subscription account and your bank statements. Also, seeing that most of these apps are for entertainment purposes, take extra precaution with your children's gadgets.

1. Beach Camera
2. Mini Camera
3. Certain Wallpaper
4. Reward Clean
5. Age Face
6. Altar Message
7. Soby Camera
8. Declare Message
9. Display Camera
10. Rapid Face Scanner
11. Leaf Face Scanner
12. Board Picture editing
13. Cute Camera
14. Dazzle Wallpaper
15. Spark Wallpaper
16. Climate SMS
17. Great VPN
18. Humour Camera
19. Print Plant scan
20. Advocate Wallpaper
21. Ruddy SMS Mod
22. Ignite Clean
23. Antivirus Security – Security Scan App Lock
24. Collate Face Scanner